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@rehmanz134 rehmanz134 closed this May 23, 2015
Rashed97 pushed a commit that referenced this pull request Jun 20, 2015
If a too small MTU value is set with ioctl(HCISETACLMTU) or by a bogus
controller, memory corruption happens due to a memcpy() call with
negative length.

Fix this crash on either incoming or outgoing connections with a MTU
smaller than L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE:

[   46.885433] BUG: unable to handle kernel paging request at f56ad000
[   46.888037] IP: [<c03d94cd>] memcpy+0x1d/0x40
[   46.888037] *pdpt = 0000000000ac3001 *pde = 00000000373f8067 *pte = 80000000356ad060
[   46.888037] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
[   46.888037] Modules linked in: hci_vhci bluetooth virtio_balloon i2c_piix4 uhci_hcd usbcore usb_common
[   46.888037] CPU: 0 PID: 1044 Comm: kworker/u3:0 Not tainted 3.10.0-rc1+ #12
[   46.888037] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[   46.888037] Workqueue: hci0 hci_rx_work [bluetooth]
[   46.888037] task: f59b15b0 ti: f55c4000 task.ti: f55c4000
[   46.888037] EIP: 0060:[<c03d94cd>] EFLAGS: 00010212 CPU: 0
[   46.888037] EIP is at memcpy+0x1d/0x40
[   46.888037] EAX: f56ac1c0 EBX: fffffff8 ECX: 3ffffc6e EDX: f55c5cf2
[   46.888037] ESI: f55c6b32 EDI: f56ad000 EBP: f55c5c68 ESP: f55c5c5c
[   46.888037]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[   46.888037] CR0: 8005003b CR2: f56ad000 CR3: 3557d000 CR4: 000006f0
[   46.888037] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[   46.888037] DR6: ffff0ff0 DR7: 00000400
[   46.888037] Stack:
[   46.888037]  fffffff8 00000010 00000003 f55c5cac f8c6a54c ffffffff f8c69eb2 00000000
[   46.888037]  f4783cdc f57f0070 f759c590 1001c580 00000003 0200000a 00000000 f5a88560
[   46.888037]  f5ba2600 f5a88560 00000041 00000000 f55c5d90 f8c6f4c7 00000008 f55c5cf2
[   46.888037] Call Trace:
[   46.888037]  [<f8c6a54c>] l2cap_send_cmd+0x1cc/0x230 [bluetooth]
[   46.888037]  [<f8c69eb2>] ? l2cap_global_chan_by_psm+0x152/0x1a0 [bluetooth]
[   46.888037]  [<f8c6f4c7>] l2cap_connect+0x3f7/0x540 [bluetooth]
[   46.888037]  [<c019b37b>] ? trace_hardirqs_off+0xb/0x10
[   46.888037]  [<c01a0ff8>] ? mark_held_locks+0x68/0x110
[   46.888037]  [<c064ad20>] ? mutex_lock_nested+0x280/0x360
[   46.888037]  [<c064b9d9>] ? __mutex_unlock_slowpath+0xa9/0x150
[   46.888037]  [<c01a118c>] ? trace_hardirqs_on_caller+0xec/0x1b0
[   46.888037]  [<c064ad08>] ? mutex_lock_nested+0x268/0x360
[   46.888037]  [<c01a125b>] ? trace_hardirqs_on+0xb/0x10
[   46.888037]  [<f8c72f8d>] l2cap_recv_frame+0xb2d/0x1d30 [bluetooth]
[   46.888037]  [<c01a0ff8>] ? mark_held_locks+0x68/0x110
[   46.888037]  [<c064b9d9>] ? __mutex_unlock_slowpath+0xa9/0x150
[   46.888037]  [<c01a118c>] ? trace_hardirqs_on_caller+0xec/0x1b0
[   46.888037]  [<f8c754f1>] l2cap_recv_acldata+0x2a1/0x320 [bluetooth]
[   46.888037]  [<f8c491d8>] hci_rx_work+0x518/0x810 [bluetooth]
[   46.888037]  [<f8c48df2>] ? hci_rx_work+0x132/0x810 [bluetooth]
[   46.888037]  [<c0158979>] process_one_work+0x1a9/0x600
[   46.888037]  [<c01588fb>] ? process_one_work+0x12b/0x600
[   46.888037]  [<c015922e>] ? worker_thread+0x19e/0x320
[   46.888037]  [<c015922e>] ? worker_thread+0x19e/0x320
[   46.888037]  [<c0159187>] worker_thread+0xf7/0x320
[   46.888037]  [<c0159090>] ? rescuer_thread+0x290/0x290
[   46.888037]  [<c01602f8>] kthread+0xa8/0xb0
[   46.888037]  [<c0656777>] ret_from_kernel_thread+0x1b/0x28
[   46.888037]  [<c0160250>] ? flush_kthread_worker+0x120/0x120
[   46.888037] Code: c3 90 8d 74 26 00 e8 63 fc ff ff eb e8 90 55 89 e5 83 ec 0c 89 5d f4 89 75 f8 89 7d fc 3e 8d 74 26 00 89 cb 89 c7 c1 e9 02 89 d6 <f3> a5 89 d9 83 e1 03 74 02 f3 a4 8b 5d f4 8b 75 f8 8b 7d fc 89
[   46.888037] EIP: [<c03d94cd>] memcpy+0x1d/0x40 SS:ESP 0068:f55c5c5c
[   46.888037] CR2: 00000000f56ad000
[   46.888037] ---[ end trace 0217c1f4d78714a9 ]---

Signed-off-by: Anderson Lizardo <[email protected]>
Signed-off-by: Gustavo Padovan <[email protected]>
Signed-off-by: John W. Linville <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Pranav Vashi <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 5, 2015
While disabling ConfigFS Android gadget, android_disconnect() calls
kill_all_hid_devices(), if CONFIG_USB_CONFIGFS_F_ACC is enabled, to free
the registered HIDs without checking whether the USB accessory device
really exist or not. If USB accessory device doesn't exist then we run into
following kernel panic:
----8<----
[  136.724761] Unable to handle kernel NULL pointer dereference at virtual address 00000064
[  136.724809] pgd = c0204000
[  136.731924] [00000064] *pgd=00000000
[  136.737830] Internal error: Oops: 5 [lg-devs#1] SMP ARM
[  136.738108] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.18.0-rc4-00400-gf75300e-dirty #76
[  136.742788] task: c0fb19d8 ti: c0fa4000 task.ti: c0fa4000
[  136.750890] PC is at _raw_spin_lock_irqsave+0x24/0x60
[  136.756246] LR is at kill_all_hid_devices+0x24/0x114
---->8----

This patch adds a test to check if USB Accessory device exists before freeing HIDs.

Change-Id: Ie229feaf0de3f4f7a151fcaa9a994e34e15ff73b
Signed-off-by: Amit Pundir <[email protected]>
(cherry picked from commit 32a71bce154cb89a549b9b7d28e8cf03b889d849)
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 5, 2015
While disabling ConfigFS Android gadget, android_disconnect() calls
kill_all_hid_devices(), if CONFIG_USB_CONFIGFS_F_ACC is enabled, to free
the registered HIDs without checking whether the USB accessory device
really exist or not. If USB accessory device doesn't exist then we run into
following kernel panic:
----8<----
[  136.724761] Unable to handle kernel NULL pointer dereference at virtual address 00000064
[  136.724809] pgd = c0204000
[  136.731924] [00000064] *pgd=00000000
[  136.737830] Internal error: Oops: 5 [lg-devs#1] SMP ARM
[  136.738108] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.18.0-rc4-00400-gf75300e-dirty #76
[  136.742788] task: c0fb19d8 ti: c0fa4000 task.ti: c0fa4000
[  136.750890] PC is at _raw_spin_lock_irqsave+0x24/0x60
[  136.756246] LR is at kill_all_hid_devices+0x24/0x114
---->8----

This patch adds a test to check if USB Accessory device exists before freeing HIDs.

Change-Id: Ie229feaf0de3f4f7a151fcaa9a994e34e15ff73b
Signed-off-by: Amit Pundir <[email protected]>
(cherry picked from commit 32a71bce154cb89a549b9b7d28e8cf03b889d849)
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 6, 2015
While disabling ConfigFS Android gadget, android_disconnect() calls
kill_all_hid_devices(), if CONFIG_USB_CONFIGFS_F_ACC is enabled, to free
the registered HIDs without checking whether the USB accessory device
really exist or not. If USB accessory device doesn't exist then we run into
following kernel panic:
----8<----
[  136.724761] Unable to handle kernel NULL pointer dereference at virtual address 00000064
[  136.724809] pgd = c0204000
[  136.731924] [00000064] *pgd=00000000
[  136.737830] Internal error: Oops: 5 [lg-devs#1] SMP ARM
[  136.738108] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.18.0-rc4-00400-gf75300e-dirty #76
[  136.742788] task: c0fb19d8 ti: c0fa4000 task.ti: c0fa4000
[  136.750890] PC is at _raw_spin_lock_irqsave+0x24/0x60
[  136.756246] LR is at kill_all_hid_devices+0x24/0x114
---->8----

This patch adds a test to check if USB Accessory device exists before freeing HIDs.

Change-Id: Ie229feaf0de3f4f7a151fcaa9a994e34e15ff73b
Signed-off-by: Amit Pundir <[email protected]>
(cherry picked from commit 32a71bce154cb89a549b9b7d28e8cf03b889d849)
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 9, 2015
Date	Wed, 10 Apr 2013 14:07:47 -0700

When switching to a new cpu_base in switch_hrtimer_base(), we
briefly enable preemption by unlocking the cpu_base lock in two
places. During this interval it's possible for the running thread
to be swapped to a different CPU.

Consider the following example:

CPU #0                                 CPU lg-devs#1
----                                   ----
hrtimer_start()                        ...
 lock_hrtimer_base()
 switch_hrtimer_base()
  this_cpu = 0;
  target_cpu_base = 0;
  raw_spin_unlock(&cpu_base->lock)
<migrate to CPU 1>
...                                    this_cpu == 0
                                       cpu == this_cpu
                                       timer->base = CPU #0
                                       timer->base != LOCAL_CPU
Since the cached this_cpu is no longer accurate, we'll skip the
hrtimer_check_target() check. Once we eventually go to program
the hardware, we'll decide not to do so since it knows the real
CPU that we're running on is not the same as the chosen base. As
a consequence, we may end up missing the hrtimer's deadline.

Fix this by updating the local CPU number each time we retake a
cpu_base lock in switch_hrtimer_base().

Another possibility is to disable preemption across the whole of
switch_hrtimer_base. This looks suboptimal since preemption
would be disabled while waiting for lock(s).

Signed-off-by: Michael Bohan <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 9, 2015
Date	Wed, 10 Apr 2013 14:07:48 -0700

When switching the hrtimer cpu_base, we briefly allow for
preemption to become enabled by unlocking the cpu_base lock.
During this time, the CPU corresponding to the new cpu_base
that was selected may in fact go offline. In this scenario, the
hrtimer is enqueued to a CPU that's not online, and therefore
it never fires.

As an example, consider this example:

CPU #0                          CPU lg-devs#1
----                            ----
...                             hrtimer_start()
                                 lock_hrtimer_base()
                                 switch_hrtimer_base()
                                  cpu = hrtimer_get_target() -> 1
                                  spin_unlock(&cpu_base->lock)
                                <migrate thread to CPU #0>
                                <offline>
spin_lock(&new_base->lock)
this_cpu = 0
cpu != this_cpu
enqueue_hrtimer(cpu_base lg-devs#1)
To prevent this scenario, verify that the CPU corresponding to
the new cpu_base is indeed online before selecting it in
hrtimer_switch_base(). If it's not online, fallback to using the
base of the current CPU.

Signed-off-by: Michael Bohan <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 9, 2015
While stressing the CPU hotplug path, sometimes we hit a problem
as shown below.

[57056.416774] ------------[ cut here ]------------
[57056.489232] ksoftirqd/1 (14): undefined instruction: pc=c01931e8
[57056.489245] Code: e594a000 eb085236 e15a0000 0a000000 (e7f001f2)
[57056.489259] ------------[ cut here ]------------
[57056.492840] kernel BUG at kernel/kernel/smpboot.c:134!
[57056.513236] Internal error: Oops - BUG: 0 [lg-devs#1] PREEMPT SMP ARM
[57056.519055] Modules linked in: wlan(O) mhi(O)
[57056.523394] CPU: 0 PID: 14 Comm: ksoftirqd/1 Tainted: G        W  O 3.10.0-g3677c61-00008-g180c060 lg-devs#1
[57056.532595] task: f0c8b000 ti: f0e78000 task.ti: f0e78000
[57056.537991] PC is at smpboot_thread_fn+0x124/0x218
[57056.542750] LR is at smpboot_thread_fn+0x11c/0x218
[57056.547528] pc : [<c01931e8>]    lr : [<c01931e0>]    psr: 200f0013
[57056.547528] sp : f0e79f30  ip : 00000000  fp : 00000000
[57056.558983] r10: 00000001  r9 : 00000000  r8 : f0e78000
[57056.564192] r7 : 00000001  r6 : c1195758  r5 : f0e78000  r4 : f0e5fd00
[57056.570701] r3 : 00000001  r2 : f0e79f20  r1 : 00000000  r0 : 00000000

This issue was always seen in the context of "ksoftirqd". It seems to
be happening because of a potential race condition in __kthread_parkme
where just after completing the parked completion, before the
ksoftirqd task has been scheduled again, it can go into running state.

Fix this by waiting for the task state to parked after waiting the
parked completion.

CRs-Fixed: 659674
Change-Id: If3f0e9b706eeb5d30d5a32f84378d35bb03fe794
Signed-off-by: Subbaraman Narayanamurthy <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 9, 2015
busy_worker_rebind_fn() didn't clear WORKER_REBIND if rebinding failed
(CPU is down again).  This used to be okay because the flag wasn't
used for anything else.

However, after 25511a4 "workqueue: reimplement CPU online rebinding
to handle idle workers", WORKER_REBIND is also used to command idle
workers to rebind.  If not cleared, the worker may confuse the next
CPU_UP cycle by having REBIND spuriously set or oops / get stuck by
prematurely calling idle_worker_rebind().

  WARNING: at /work/os/wq/kernel/workqueue.c:1323 worker_thread+0x4cd/0x5
 00()
  Hardware name: Bochs
  Modules linked in: test_wq(O-)
  Pid: 33, comm: kworker/1:1 Tainted: G           O 3.6.0-rc1-work+ lg-devs#3
  Call Trace:
   [<ffffffff8109039f>] warn_slowpath_common+0x7f/0xc0
   [<ffffffff810903fa>] warn_slowpath_null+0x1a/0x20
   [<ffffffff810b3f1d>] worker_thread+0x4cd/0x500
   [<ffffffff810bc16e>] kthread+0xbe/0xd0
   [<ffffffff81bd2664>] kernel_thread_helper+0x4/0x10
  ---[ end trace e977cf20f4661968 ]---
  BUG: unable to handle kernel NULL pointer dereference at           (null)
  IP: [<ffffffff810b3db0>] worker_thread+0x360/0x500
  PGD 0
  Oops: 0000 [lg-devs#1] PREEMPT SMP DEBUG_PAGEALLOC
  Modules linked in: test_wq(O-)
  CPU 0
  Pid: 33, comm: kworker/1:1 Tainted: G        W  O 3.6.0-rc1-work+ lg-devs#3 Bochs Bochs
  RIP: 0010:[<ffffffff810b3db0>]  [<ffffffff810b3db0>] worker_thread+0x360/0x500
  RSP: 0018:ffff88001e1c9de0  EFLAGS: 00010086
  RAX: 0000000000000000 RBX: ffff88001e633e00 RCX: 0000000000004140
  RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000009
  RBP: ffff88001e1c9ea0 R08: 0000000000000000 R09: 0000000000000001
  R10: 0000000000000002 R11: 0000000000000000 R12: ffff88001fc8d580
  R13: ffff88001fc8d590 R14: ffff88001e633e20 R15: ffff88001e1c6900
  FS:  0000000000000000(0000) GS:ffff88001fc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 0000000000000000 CR3: 00000000130e8000 CR4: 00000000000006f0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
  Process kworker/1:1 (pid: 33, threadinfo ffff88001e1c8000, task ffff88001e1c6900)
  Stack:
   ffff880000000000 ffff88001e1c9e40 0000000000000001 ffff88001e1c8010
   ffff88001e519c78 ffff88001e1c9e58 ffff88001e1c6900 ffff88001e1c6900
   ffff88001e1c6900 ffff88001e1c6900 ffff88001fc8d340 ffff88001fc8d340
  Call Trace:
   [<ffffffff810bc16e>] kthread+0xbe/0xd0
   [<ffffffff81bd2664>] kernel_thread_helper+0x4/0x10
  Code: b1 00 f6 43 48 02 0f 85 91 01 00 00 48 8b 43 38 48 89 df 48 8b 00 48 89 45 90 e8 ac f0 ff ff 3c 01 0f 85 60 01 00 00 48 8b 53 50 <8b> 02 83 e8 01 85 c0 89 02 0f 84 3b 01 00 00 48 8b 43 38 48 8b
  RIP  [<ffffffff810b3db0>] worker_thread+0x360/0x500
   RSP <ffff88001e1c9de0>
  CR2: 0000000000000000

There was no reason to keep WORKER_REBIND on failure in the first
place - WORKER_UNBOUND is guaranteed to be set in such cases
preventing incorrectly activating concurrency management.  Always
clear WORKER_REBIND.

tj: Updated comment and description.

Signed-off-by: Lai Jiangshan <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>

    master

    v3.17-rc2
    …
    v3.6

commit 960bd11bf2daf669d0d910428fd9ef5a15c3d7cb 1 parent ee378aa
Lai Jiangshan laijs authored on Sep 18, 2012
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 9, 2015
On a KVM guest, when a CPU is taken offline and brought back online, we hit
the following NULL pointer dereference:

[   45.400843] Unregister pv shared memory for cpu 1
[   45.412331] smpboot: CPU 1 is now offline
[   45.529894] SMP alternatives: lockdep: fixing up alternatives
[   45.533472] smpboot: Booting Node 0 Processor 1 APIC 0x1
[   45.411526] kvm-clock: cpu 1, msr 0:7d14601, secondary cpu clock
[   45.571370] KVM setup async PF for cpu 1
[   45.572331] kvm-stealtime: cpu 1, msr 7d0e040
[   45.575031] BUG: unable to handle kernel NULL pointer dereference at           (null)
[   45.576017] IP: [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[   45.576017] PGD 5dfb067 PUD 5da8067 PMD 0
[   45.576017] Oops: 0000 [lg-devs#1] SMP
[   45.576017] Modules linked in:
[   45.576017] CPU 0
[   45.576017] Pid: 607, comm: stress_cpu_hotp Not tainted 3.6.0-padata-tp-debug lg-devs#3 Bochs Bochs
[   45.576017] RIP: 0010:[<ffffffff81519f98>]  [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[   45.576017] RSP: 0018:ffff880005d93ce8  EFLAGS: 00010286
[   45.576017] RAX: ffff880005d93fd8 RBX: 0000000000000000 RCX: 0000000000000006
[   45.576017] RDX: 0000000000000006 RSI: 2222222222222222 RDI: 0000000000000000
[   45.576017] RBP: ffff880005d93cf8 R08: 2222222222222222 R09: 2222222222222222
[   45.576017] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[   45.576017] R13: 0000000000000000 R14: ffffffff81c8cca0 R15: 0000000000000001
[   45.576017] FS:  00007f91936ae700(0000) GS:ffff880007c00000(0000) knlGS:0000000000000000
[   45.576017] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   45.576017] CR2: 0000000000000000 CR3: 0000000005db3000 CR4: 00000000000006f0
[   45.576017] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   45.576017] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   45.576017] Process stress_cpu_hotp (pid: 607, threadinfo ffff880005d92000, task ffff8800066bbf40)
[   45.576017] Stack:
[   45.576017]  ffff880007a96400 0000000000000000 ffff880005d93d28 ffffffff813ac689
[   45.576017]  ffff880007a96400 ffff880007a96400 0000000000000002 ffffffff81cd8d01
[   45.576017]  ffff880005d93d58 ffffffff813aa498 0000000000000001 00000000ffffffdd
[   45.576017] Call Trace:
[   45.576017]  [<ffffffff813ac689>] acpi_processor_hotplug+0x55/0x97
[   45.576017]  [<ffffffff813aa498>] acpi_cpu_soft_notify+0x93/0xce
[   45.576017]  [<ffffffff816ae47d>] notifier_call_chain+0x5d/0x110
[   45.576017]  [<ffffffff8109730e>] __raw_notifier_call_chain+0xe/0x10
[   45.576017]  [<ffffffff81069050>] __cpu_notify+0x20/0x40
[   45.576017]  [<ffffffff81069085>] cpu_notify+0x15/0x20
[   45.576017]  [<ffffffff816978f1>] _cpu_up+0xee/0x137
[   45.576017]  [<ffffffff81697983>] cpu_up+0x49/0x59
[   45.576017]  [<ffffffff8168758d>] store_online+0x9d/0xe0
[   45.576017]  [<ffffffff8140a9f8>] dev_attr_store+0x18/0x30
[   45.576017]  [<ffffffff812322c0>] sysfs_write_file+0xe0/0x150
[   45.576017]  [<ffffffff811b389c>] vfs_write+0xac/0x180
[   45.576017]  [<ffffffff811b3be2>] sys_write+0x52/0xa0
[   45.576017]  [<ffffffff816b31e9>] system_call_fastpath+0x16/0x1b
[   45.576017] Code: 48 c7 c7 40 e5 ca 81 e8 07 d0 18 00 5d c3 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 10 48 89 5d f0 4c 89 65 f8 48 89 fb <f6> 07 02 75 13 48 8b 5d f0 4c 8b 65 f8 c9 c3 66 0f 1f 84 00 00
[   45.576017] RIP  [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[   45.576017]  RSP <ffff880005d93ce8>
[   45.576017] CR2: 0000000000000000
[   45.656079] ---[ end trace 433d6c9ac0b02cef ]---

Analysis:
Commit 3d339dc (cpuidle / ACPI : move cpuidle_device field out of the
acpi_processor_power structure()) made the allocation of the dev structure
(struct cpuidle) of a CPU dynamic, whereas previously it was statically
allocated. And this dynamic allocation occurs in acpi_processor_power_init()
if pr->flags.power evaluates to non-zero.

On KVM guests, pr->flags.power evaluates to zero, hence dev is never
allocated. This causes the NULL pointer (dev) dereference in
cpuidle_disable_device() during a subsequent CPU online operation. Fix this
by ensuring that dev is non-NULL before dereferencing.

Signed-off-by: Srivatsa S. Bhat <[email protected]>
Signed-off-by: Len Brown <[email protected]>
Signed-off-by: Pranav Vashi <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 9, 2015
I saw this suspicious RCU usage on the next tree of 11/15

[   67.123404] ===============================
[   67.123413] [ INFO: suspicious RCU usage. ]
[   67.123423] 3.7.0-rc5-next-20121115-dirty lg-devs#1 Not tainted
[   67.123434] -------------------------------
[   67.123444] include/trace/events/timer.h:186 suspicious rcu_dereference_check() usage!
[   67.123458]
[   67.123458] other info that might help us debug this:
[   67.123458]
[   67.123474]
[   67.123474] RCU used illegally from idle CPU!
[   67.123474] rcu_scheduler_active = 1, debug_locks = 0
[   67.123493] RCU used illegally from extended quiescent state!
[   67.123507] 1 lock held by swapper/1/0:
[   67.123516]  #0:  (&cpu_base->lock){-.-...}, at: [<c0000000000979b0>] .__hrtimer_start_range_ns+0x28c/0x524
[   67.123555]
[   67.123555] stack backtrace:
[   67.123566] Call Trace:
[   67.123576] [c0000001e2ccb920] [c00000000001275c] .show_stack+0x78/0x184 (unreliable)
[   67.123599] [c0000001e2ccb9d0] [c0000000000c15a0] .lockdep_rcu_suspicious+0x120/0x148
[   67.123619] [c0000001e2ccba70] [c00000000009601c] .enqueue_hrtimer+0x1c0/0x1c8
[   67.123639] [c0000001e2ccbb00] [c000000000097aa0] .__hrtimer_start_range_ns+0x37c/0x524
[   67.123660] [c0000001e2ccbc20] [c0000000005c9698] .menu_select+0x508/0x5bc
[   67.123678] [c0000001e2ccbd20] [c0000000005c740c] .cpuidle_idle_call+0xa8/0x6e4
[   67.123699] [c0000001e2ccbdd0] [c0000000000459a0] .pSeries_idle+0x10/0x34
[   67.123717] [c0000001e2ccbe40] [c000000000014dc8] .cpu_idle+0x130/0x280
[   67.123738] [c0000001e2ccbee0] [c0000000006ffa8c] .start_secondary+0x378/0x384
[   67.123758] [c0000001e2ccbf90] [c00000000000936c] .start_secondary_prolog+0x10/0x14

hrtimer_start was added in 198fd638 and ae515197. The patch below tries
to use RCU_NONIDLE around it to avoid the above report.

Signed-off-by: Li Zhong <[email protected]>
Acked-by: Paul E. McKenney <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Pranav Vashi <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 9, 2015
Commit b81ea1b (PM / QoS: Fix concurrency issues and memory leaks in
device PM QoS) put calls to pm_qos_sysfs_add_latency(),
pm_qos_sysfs_add_flags(), pm_qos_sysfs_remove_latency(), and
pm_qos_sysfs_remove_flags() under dev_pm_qos_mtx, which was a
mistake, because it may lead to deadlocks in some situations.
For example, if pm_qos_remote_wakeup_store() is run in parallel
with dev_pm_qos_constraints_destroy(), they may deadlock in the
following way:

 ======================================================
 [ INFO: possible circular locking dependency detected ]
 3.9.0-rc4-next-20130328-sasha-00014-g91a3267 #319 Tainted: G        W
 -------------------------------------------------------
 trinity-child6/12371 is trying to acquire lock:
  (s_active#54){++++.+}, at: [<ffffffff81301631>] sysfs_addrm_finish+0x31/0x60

 but task is already holding lock:
  (dev_pm_qos_mtx){+.+.+.}, at: [<ffffffff81f07cc3>] dev_pm_qos_constraints_destroy+0x23/0x250

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> lg-devs#1 (dev_pm_qos_mtx){+.+.+.}:
        [<ffffffff811811da>] lock_acquire+0x1aa/0x240
        [<ffffffff83dab809>] __mutex_lock_common+0x59/0x5e0
        [<ffffffff83dabebf>] mutex_lock_nested+0x3f/0x50
        [<ffffffff81f07f2f>] dev_pm_qos_update_flags+0x3f/0xc0
        [<ffffffff81f05f4f>] pm_qos_remote_wakeup_store+0x3f/0x70
        [<ffffffff81efbb43>] dev_attr_store+0x13/0x20
        [<ffffffff812ffdaa>] sysfs_write_file+0xfa/0x150
        [<ffffffff8127f2c1>] __kernel_write+0x81/0x150
        [<ffffffff812afc2d>] write_pipe_buf+0x4d/0x80
        [<ffffffff812af57c>] splice_from_pipe_feed+0x7c/0x120
        [<ffffffff812afa25>] __splice_from_pipe+0x45/0x80
        [<ffffffff812b14fc>] splice_from_pipe+0x4c/0x70
        [<ffffffff812b1538>] default_file_splice_write+0x18/0x30
        [<ffffffff812afae3>] do_splice_from+0x83/0xb0
        [<ffffffff812afb2e>] direct_splice_actor+0x1e/0x20
        [<ffffffff812b0277>] splice_direct_to_actor+0xe7/0x200
        [<ffffffff812b15bc>] do_splice_direct+0x4c/0x70
        [<ffffffff8127eda9>] do_sendfile+0x169/0x300
        [<ffffffff8127ff94>] SyS_sendfile64+0x64/0xb0
        [<ffffffff83db7d18>] tracesys+0xe1/0xe6

 -> #0 (s_active#54){++++.+}:
        [<ffffffff811800cf>] __lock_acquire+0x15bf/0x1e50
        [<ffffffff811811da>] lock_acquire+0x1aa/0x240
        [<ffffffff81300aa2>] sysfs_deactivate+0x122/0x1a0
        [<ffffffff81301631>] sysfs_addrm_finish+0x31/0x60
        [<ffffffff812ff77f>] sysfs_hash_and_remove+0x7f/0xb0
        [<ffffffff813035a1>] sysfs_unmerge_group+0x51/0x70
        [<ffffffff81f068f4>] pm_qos_sysfs_remove_flags+0x14/0x20
        [<ffffffff81f07490>] __dev_pm_qos_hide_flags+0x30/0x70
        [<ffffffff81f07cd5>] dev_pm_qos_constraints_destroy+0x35/0x250
        [<ffffffff81f06931>] dpm_sysfs_remove+0x11/0x50
        [<ffffffff81efcf6f>] device_del+0x3f/0x1b0
        [<ffffffff81efd128>] device_unregister+0x48/0x60
        [<ffffffff82d4083c>] usb_hub_remove_port_device+0x1c/0x20
        [<ffffffff82d2a9cd>] hub_disconnect+0xdd/0x160
        [<ffffffff82d36ab7>] usb_unbind_interface+0x67/0x170
        [<ffffffff81f001a7>] __device_release_driver+0x87/0xe0
        [<ffffffff81f00559>] device_release_driver+0x29/0x40
        [<ffffffff81effc58>] bus_remove_device+0x148/0x160
        [<ffffffff81efd07f>] device_del+0x14f/0x1b0
        [<ffffffff82d344f9>] usb_disable_device+0xf9/0x280
        [<ffffffff82d34ff8>] usb_set_configuration+0x268/0x840
        [<ffffffff82d3a7fc>] usb_remove_store+0x4c/0x80
        [<ffffffff81efbb43>] dev_attr_store+0x13/0x20
        [<ffffffff812ffdaa>] sysfs_write_file+0xfa/0x150
        [<ffffffff8127f71d>] do_loop_readv_writev+0x4d/0x90
        [<ffffffff8127f999>] do_readv_writev+0xf9/0x1e0
        [<ffffffff8127faba>] vfs_writev+0x3a/0x60
        [<ffffffff8127fc60>] SyS_writev+0x50/0xd0
        [<ffffffff83db7d18>] tracesys+0xe1/0xe6

 other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(dev_pm_qos_mtx);
                                lock(s_active#54);
                                lock(dev_pm_qos_mtx);
   lock(s_active#54);

  *** DEADLOCK ***

To avoid that, remove the calls to functions mentioned above from
under dev_pm_qos_mtx and introduce a separate lock to prevent races
between functions that add or remove device PM QoS sysfs attributes
from happening.

Reported-by: Sasha Levin <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 9, 2015
BUG lg-devs#1) All places where we call ext4_flush_completed_IO are broken
    because buffered io and DIO/AIO goes through three stages
    1) submitted io,
    2) completed io (in i_completed_io_list) conversion pended
    3) finished  io (conversion done)
    And by calling ext4_flush_completed_IO we will flush only
    requests which were in (2) stage, which is wrong because:
     1) punch_hole and truncate _must_ wait for all outstanding unwritten io
      regardless to it's state.
     2) fsync and nolock_dio_read should also wait because there is
        a time window between end_page_writeback() and ext4_add_complete_io()
        As result integrity fsync is broken in case of buffered write
        to fallocated region:
        fsync                                      blkdev_completion
	 ->filemap_write_and_wait_range
                                                   ->ext4_end_bio
                                                     ->end_page_writeback
          <-- filemap_write_and_wait_range return
	 ->ext4_flush_completed_IO
   	 sees empty i_completed_io_list but pended
   	 conversion still exist
                                                     ->ext4_add_complete_io

BUG lg-devs#2) Race window becomes wider due to the 'ext4: completed_io
locking cleanup V4' patch series

This patch make following changes:
1) ext4_flush_completed_io() now first try to flush completed io and when
   wait for any outstanding unwritten io via ext4_unwritten_wait()
2) Rename function to more appropriate name.
3) Assert that all callers of ext4_flush_unwritten_io should hold i_mutex to
   prevent endless wait

Signed-off-by: Dmitry Monakhov <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 10, 2015
There are a couple of seq_files which use the single_open() interface.
This interface requires that the whole output must fit into a single
buffer.

E.g.  for /proc/stat allocation failures have been observed because an
order-4 memory allocation failed due to memory fragmentation.  In such
situations reading /proc/stat is not possible anymore.

Therefore change the seq_file code to fallback to vmalloc allocations
which will usually result in a couple of order-0 allocations and hence
also work if memory is fragmented.

For reference a call trace where reading from /proc/stat failed:

  sadc: page allocation failure: order:4, mode:0x1040d0
  CPU: 1 PID: 192063 Comm: sadc Not tainted 3.10.0-123.el7.s390x lg-devs#1
  [...]
  Call Trace:
    show_stack+0x6c/0xe8
    warn_alloc_failed+0xd6/0x138
    __alloc_pages_nodemask+0x9da/0xb68
    __get_free_pages+0x2e/0x58
    kmalloc_order_trace+0x44/0xc0
    stat_open+0x5a/0xd8
    proc_reg_open+0x8a/0x140
    do_dentry_open+0x1bc/0x2c8
    finish_open+0x46/0x60
    do_last+0x382/0x10d0
    path_openat+0xc8/0x4f8
    do_filp_open+0x46/0xa8
    do_sys_open+0x114/0x1f0
    sysc_tracego+0x14/0x1a

Signed-off-by: Heiko Carstens <[email protected]>
Tested-by: David Rientjes <[email protected]>
Cc: Ian Kent <[email protected]>
Cc: Hendrik Brueckner <[email protected]>
Cc: Thorsten Diehl <[email protected]>
Cc: Andrea Righi <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Stefan Bader <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Pranav Vashi <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 10, 2015
Commit 1331e7a1bbe1 ("rcu: Remove _rcu_barrier() dependency on
__stop_machine()") introduced slab_mutex -> cpu_hotplug.lock dependency
through kmem_cache_destroy() -> rcu_barrier() -> _rcu_barrier() ->
get_online_cpus().

Lockdep thinks that this might actually result in ABBA deadlock,
and reports it as below:

=== [ cut here ] ===
 ======================================================
 [ INFO: possible circular locking dependency detected ]
 3.6.0-rc5-00004-g0d8ee37 #143 Not tainted
 -------------------------------------------------------
 kworker/u:2/40 is trying to acquire lock:
  (rcu_sched_state.barrier_mutex){+.+...}, at: [<ffffffff810f2126>] _rcu_barrier+0x26/0x1e0

 but task is already holding lock:
  (slab_mutex){+.+.+.}, at: [<ffffffff81176e15>] kmem_cache_destroy+0x45/0xe0

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> lg-devs#2 (slab_mutex){+.+.+.}:
        [<ffffffff810ae1e2>] validate_chain+0x632/0x720
        [<ffffffff810ae5d9>] __lock_acquire+0x309/0x530
        [<ffffffff810ae921>] lock_acquire+0x121/0x190
        [<ffffffff8155d4cc>] __mutex_lock_common+0x5c/0x450
        [<ffffffff8155d9ee>] mutex_lock_nested+0x3e/0x50
        [<ffffffff81558cb5>] cpuup_callback+0x2f/0xbe
        [<ffffffff81564b83>] notifier_call_chain+0x93/0x140
        [<ffffffff81076f89>] __raw_notifier_call_chain+0x9/0x10
        [<ffffffff8155719d>] _cpu_up+0xba/0x14e
        [<ffffffff815572ed>] cpu_up+0xbc/0x117
        [<ffffffff81ae05e3>] smp_init+0x6b/0x9f
        [<ffffffff81ac47d6>] kernel_init+0x147/0x1dc
        [<ffffffff8156ab44>] kernel_thread_helper+0x4/0x10

 -> lg-devs#1 (cpu_hotplug.lock){+.+.+.}:
        [<ffffffff810ae1e2>] validate_chain+0x632/0x720
        [<ffffffff810ae5d9>] __lock_acquire+0x309/0x530
        [<ffffffff810ae921>] lock_acquire+0x121/0x190
        [<ffffffff8155d4cc>] __mutex_lock_common+0x5c/0x450
        [<ffffffff8155d9ee>] mutex_lock_nested+0x3e/0x50
        [<ffffffff81049197>] get_online_cpus+0x37/0x50
        [<ffffffff810f21bb>] _rcu_barrier+0xbb/0x1e0
        [<ffffffff810f22f0>] rcu_barrier_sched+0x10/0x20
        [<ffffffff810f2309>] rcu_barrier+0x9/0x10
        [<ffffffff8118c129>] deactivate_locked_super+0x49/0x90
        [<ffffffff8118cc01>] deactivate_super+0x61/0x70
        [<ffffffff811aaaa7>] mntput_no_expire+0x127/0x180
        [<ffffffff811ab49e>] sys_umount+0x6e/0xd0
        [<ffffffff81569979>] system_call_fastpath+0x16/0x1b

 -> #0 (rcu_sched_state.barrier_mutex){+.+...}:
        [<ffffffff810adb4e>] check_prev_add+0x3de/0x440
        [<ffffffff810ae1e2>] validate_chain+0x632/0x720
        [<ffffffff810ae5d9>] __lock_acquire+0x309/0x530
        [<ffffffff810ae921>] lock_acquire+0x121/0x190
        [<ffffffff8155d4cc>] __mutex_lock_common+0x5c/0x450
        [<ffffffff8155d9ee>] mutex_lock_nested+0x3e/0x50
        [<ffffffff810f2126>] _rcu_barrier+0x26/0x1e0
        [<ffffffff810f22f0>] rcu_barrier_sched+0x10/0x20
        [<ffffffff810f2309>] rcu_barrier+0x9/0x10
        [<ffffffff81176ea1>] kmem_cache_destroy+0xd1/0xe0
        [<ffffffffa04c3154>] nf_conntrack_cleanup_net+0xe4/0x110 [nf_conntrack]
        [<ffffffffa04c31aa>] nf_conntrack_cleanup+0x2a/0x70 [nf_conntrack]
        [<ffffffffa04c42ce>] nf_conntrack_net_exit+0x5e/0x80 [nf_conntrack]
        [<ffffffff81454b79>] ops_exit_list+0x39/0x60
        [<ffffffff814551ab>] cleanup_net+0xfb/0x1b0
        [<ffffffff8106917b>] process_one_work+0x26b/0x4c0
        [<ffffffff81069f3e>] worker_thread+0x12e/0x320
        [<ffffffff8106f73e>] kthread+0x9e/0xb0
        [<ffffffff8156ab44>] kernel_thread_helper+0x4/0x10

 other info that might help us debug this:

 Chain exists of:
   rcu_sched_state.barrier_mutex --> cpu_hotplug.lock --> slab_mutex

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(slab_mutex);
                                lock(cpu_hotplug.lock);
                                lock(slab_mutex);
   lock(rcu_sched_state.barrier_mutex);

  *** DEADLOCK ***
=== [ cut here ] ===

This is actually a false positive. Lockdep has no way of knowing the fact
that the ABBA can actually never happen, because of special semantics of
cpu_hotplug.refcount and its handling in cpu_hotplug_begin(); the mutual
exclusion there is not achieved through mutex, but through
cpu_hotplug.refcount.

The "neither cpu_up() nor cpu_down() will proceed past cpu_hotplug_begin()
until everyone who called get_online_cpus() will call put_online_cpus()"
semantics is totally invisible to lockdep.

This patch therefore moves the unlock of slab_mutex so that rcu_barrier()
is being called with it unlocked. It has two advantages:

- it slightly reduces hold time of slab_mutex; as it's used to protect
  the cachep list, it's not necessary to hold it over kmem_cache_free()
  call any more
- it silences the lockdep false positive warning, as it avoids lockdep ever
  learning about slab_mutex -> cpu_hotplug.lock dependency

Reviewed-by: Paul E. McKenney <[email protected]>
Reviewed-by: Srivatsa S. Bhat <[email protected]>
Acked-by: David Rientjes <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
Signed-off-by: Pekka Enberg <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 10, 2015
This prevents the following crash seen during boot-up:
Unable to handle kernel NULL pointer dereference at virtual address 00000041
pgd = ffffffc037f68000
[00000041] *pgd=0000000000000000
Internal error: Oops: 96000005 [lg-devs#1] PREEMPT SMP
Modules linked in: inv_bmp180 inv_ak8975 inv_mpu
CPU: 0 PID: 1457 Comm: IntentService[F Not tainted 3.10.40-g4abcb3f lg-devs#1
task: ffffffc0393e0080 ti: ffffffc0393e8000 task.ti: ffffffc0393e8000
PC is at follow_page_mask+0x1c/0x378
LR is at __get_user_pages.part.88+0x124/0x700
pc : [<ffffffc00016c314>] lr : [<ffffffc00016e1d4>] pstate: 40000045

Bug 1525355

Change-Id: Ieed6942d7beb32964484f97d5cc671b42c4b60cb
Signed-off-by: Bharat Nihalani <[email protected]>
Reviewed-on: http://git-master/r/427723
Tested-by: Vandana Salve <[email protected]>
Reviewed-by: Krishna Reddy <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 13, 2015
On ARMv7 CPUs that cache first level page table entries (like the
Cortex-A15), using a reserved ASID while changing the TTBR or flushing
the TLB is unsafe.

This is because the CPU may cache the first level entry as the result of
a speculative memory access while the reserved ASID is assigned. After
the process owning the page tables dies, the memory will be reallocated
and may be written with junk values which can be interpreted as global,
valid PTEs by the processor. This will result in the TLB being populated
with bogus global entries.

This patch avoids the use of a reserved context ID in the v7 switch_mm
and ASID rollover code by temporarily using the swapper_pg_dir pointed
at by TTBR1, which contains only global entries that are not tagged
with ASIDs.

Reviewed-by: Frank Rowand <[email protected]>
Tested-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
[[email protected]: add LPAE support]
Signed-off-by: Catalin Marinas <[email protected]>

Change-Id: I2dd82501dac5ee402765aaa0ffb3f7f577a603c9

ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on ASID-capable CPUs

Since the ASIDs must be unique to an mm across all the CPUs in a system,
the __new_context() function needs to broadcast a context reset event to
all the CPUs during ASID allocation if a roll-over occurred. Such IPIs
cannot be issued with interrupts disabled and ARM had to define
__ARCH_WANT_INTERRUPTS_ON_CTXSW.

This patch changes the check_context() function to
check_and_switch_context() called from switch_mm(). In case of
ASID-capable CPUs (ARMv6 onwards), if a new ASID is needed and the
interrupts are disabled, it defers the __new_context() and
cpu_switch_mm() calls to the post-lock switch hook where the interrupts
are enabled. Setting the reserved TTBR0 was also moved to
check_and_switch_context() from cpu_v7_switch_mm().

Reviewed-by: Will Deacon <[email protected]>
Tested-by: Will Deacon <[email protected]>
Reviewed-by: Frank Rowand <[email protected]>
Tested-by: Marc Zyngier <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>

Conflicts:
	arch/arm/mm/proc-v7-2level.S

Change-Id: I48e39730c49ff8d30ce566e8a03cf54557869a52

ARM: Remove current_mm per-cpu variable

The current_mm variable was used to store the new mm between the
switch_mm() and switch_to() calls where an IPI to reset the context
could have set the wrong mm. Since the interrupts are disabled during
context switch, there is no need for this variable, current->active_mm
already points to the current mm when interrupts are re-enabled.

Reviewed-by: Will Deacon <[email protected]>
Tested-by: Will Deacon <[email protected]>
Reviewed-by: Frank Rowand <[email protected]>
Tested-by: Marc Zyngier <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>

ARM: 7502/1: contextidr: avoid using bfi instruction during notifier

The bfi instruction is not available on ARMv6, so instead use an and/orr
sequence in the contextidr_notifier. This gets rid of the assembler
error:

  Assembler messages:
  Error: selected processor does not support ARM mode `bfi r3,r2,#0,lg-devs#8'

Reported-by: Arnd Bergmann <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Russell King <[email protected]>

Conflicts:
	arch/arm/mm/context.c

Change-Id: Id64c0145d0dcd1cfe9e2aba59f86c08ec5fbf649

ARM: mm: remove IPI broadcasting on ASID rollover

ASIDs are allocated to MMU contexts based on a rolling counter. This
means that after 255 allocations we must invalidate all existing ASIDs
via an expensive IPI mechanism to synchronise all of the online CPUs and
ensure that all tasks execute with an ASID from the new generation.

This patch changes the rollover behaviour so that we rely instead on the
hardware broadcasting of the TLB invalidation to avoid the IPI calls.
This works by keeping track of the active ASID on each core, which is
then reserved in the case of a rollover so that currently scheduled
tasks can continue to run. For cores without hardware TLB broadcasting,
we keep track of pending flushes in a cpumask, so cores can flush their
local TLB before scheduling a new mm.

Reviewed-by: Catalin Marinas <[email protected]>
Tested-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

Conflicts:
	arch/arm/mm/context.c

Change-Id: I58990400aaaaef35319f7b3fb2f84fe7e46cb581

ARM: mm: avoid taking ASID spinlock on fastpath

When scheduling a new mm, we take a spinlock so that we can:

  1. Safely allocate a new ASID, if required
  2. Update our active_asids field without worrying about parallel
     updates to reserved_asids
  3. Ensure that we flush our local TLB, if required

However, this has the nasty affect of serialising context-switch across
all CPUs in the system. The usual (fast) case is where the next mm has
a valid ASID for the current generation. In such a scenario, we can
avoid taking the lock and instead use atomic64_xchg to update the
active_asids variable for the current CPU. If a rollover occurs on
another CPU (which would take the lock), when copying the active_asids
into the reserved_asids another atomic64_xchg is used to replace each
active_asids with 0. The fast path can then detect this case and fall
back to spinning on the lock.

Tested-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

ARM: mm: use bitmap operations when allocating new ASIDs

When allocating a new ASID, we must take care not to re-assign a
reserved ASID-value to a new mm. This requires us to check each
candidate ASID against those currently reserved by other cores before
assigning a new ASID to the current mm.

This patch improves the ASID allocation algorithm by using a
bitmap-based approach. Rather than iterating over the reserved ASID
array for each candidate ASID, we simply find the first zero bit,
ensuring that those indices corresponding to reserved ASIDs are set
when flushing during a rollover event.

Tested-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

ARM: 7649/1: mm: mm->context.id fix for big-endian

Since the new ASID code in b5466f8728527a05a493cc4abe9e6f034a1bbaab
("ARM: mm: remove IPI broadcasting on ASID rollover") was changed to
use 64bit operations it has broken the BE operation due to an issue
with the MM code accessing sub-fields of mm->context.id.

When running in BE mode we see the values in mm->context.id are stored
with the highest value first, so the LDR in the arch/arm/mm/proc-macros.S
reads the wrong part of this field. To resolve this, change the LDR in
the mmid macro to load from +4.

Acked-by: Will Deacon <[email protected]>
Signed-off-by: Ben Dooks <[email protected]>
Signed-off-by: Russell King <[email protected]>

ARM: 7658/1: mm: fix race updating mm->context.id on ASID rollover

If a thread triggers an ASID rollover, other threads of the same process
must be made to wait until the mm->context.id for the shared mm_struct
has been updated to new generation and associated book-keeping (e.g.
TLB invalidation) has ben performed.

However, there is a *tiny* window where both mm->context.id and the
relevant active_asids entry are updated to the new generation, but the
TLB flush has not been performed, which could allow another thread to
return to userspace with a dirty TLB, potentially leading to data
corruption. In reality this will never occur because one CPU would need
to perform a context-switch in the time it takes another to do a couple
of atomic test/set operations but we should plug the race anyway.

This patch moves the active_asids update until after the potential TLB
flush on context-switch.

Cc: <[email protected]> # 3.8
Reviewed-by: Catalin Marinas <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Russell King <[email protected]>

ARM: 7659/1: mm: make mm->context.id an atomic64_t variable

mm->context.id is updated under asid_lock when a new ASID is allocated
to an mm_struct. However, it is also read without the lock when a task
is being scheduled and checking whether or not the current ASID
generation is up-to-date.

If two threads of the same process are being scheduled in parallel and
the bottom bits of the generation in their mm->context.id match the
current generation (that is, the mm_struct has not been used for ~2^24
rollovers) then the non-atomic, lockless access to mm->context.id may
yield the incorrect ASID.

This patch fixes this issue by making mm->context.id and atomic64_t,
ensuring that the generation is always read consistently. For code that
only requires access to the ASID bits (e.g. TLB flushing by mm), then
the value is accessed directly, which GCC converts to an ldrb.

Cc: <[email protected]> # 3.8
Reviewed-by: Catalin Marinas <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Russell King <[email protected]>

Conflicts:
	arch/arm/include/asm/mmu.h

Change-Id: I682895d6357a91ecc439c8543fa94f1aecbfcb4c

ARM: 7661/1: mm: perform explicit branch predictor maintenance when required

The ARM ARM requires branch predictor maintenance if, for a given ASID,
the instructions at a specific virtual address appear to change.

From the kernel's point of view, that means:

	- Changing the kernel's view of memory (e.g. switching to the
	  identity map)
	- ASID rollover (since ASIDs will be re-allocated to new tasks)

This patch adds explicit branch predictor maintenance when either of the
two conditions above are met.

Reviewed-by: Catalin Marinas <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Russell King <[email protected]>

ARM: 7684/1: errata: Workaround for Cortex-A15 erratum 798181 (TLBI/DSB operations)

On Cortex-A15 (r0p0..r3p2) the TLBI/DSB are not adequately shooting down
all use of the old entries. This patch implements the erratum workaround
which consists of:

1. Dummy TLBIMVAIS and DSB on the CPU doing the TLBI operation.
2. Send IPI to the CPUs that are running the same mm (and ASID) as the
   one being invalidated (or all the online CPUs for global pages).
3. CPU receiving the IPI executes a DMB and CLREX (part of the exception
   return code already).

Signed-off-by: Catalin Marinas <[email protected]>
Signed-off-by: Russell King <[email protected]>

Conflicts:
	arch/arm/Kconfig

Change-Id: I4513d042301a1faad817b83434280462cc176df1

msm: rtb: Log the context id in the rtb

Store the context id in the register trace buffer.
The process id can be derived from the context id.
This gives a general idea about what process was last
running when the RTB stopped.

Change-Id: I2fb8934d008b8cf3666f1df2652846c15faca776
Signed-off-by: Laura Abbott <[email protected]>
(cherry picked from commit 445eb9a)

Conflicts:

	arch/arm/mach-msm/include/mach/msm_rtb.h

ARM: 7767/1: let the ASID allocator handle suspended animation

commit ae120d9edfe96628f03d87634acda0bfa7110632 upstream.

When a CPU is running a process, the ASID for that process is
held in a per-CPU variable (the "active ASIDs" array). When
the ASID allocator handles a rollover, it copies the active
ASIDs into a "reserved ASIDs" array to ensure that a process
currently running on another CPU will continue to run unaffected.
The active array is zero-ed to indicate that a rollover occurred.

Because of this mechanism, a reserved ASID is only remembered for
a single rollover. A subsequent rollover will completely refill
the reserved ASIDs array.

In a severely oversubscribed environment where a CPU can be
prevented from running for extended periods of time (think virtual
machines), the above has a horrible side effect:

[P{a} denotes process P running with ASID a]

	CPU-0		CPU-1

	A{x}				[active = <x 0>]

	[suspended]	runs B{y}	[active = <x y>]

					[rollover:
					 active = <0 0>
					 reserved = <x y>]

			runs B{y}	[active = <0 y>
					 reserved = <x y>]

					[rollover:
					 active = <0 0>
					 reserved = <0 y>]

			runs C{x}	[active = <0 x>]

	[resumes]

	runs A{x}

At that stage, both A and C have the same ASID, with deadly
consequences.

The fix is to preserve reserved ASIDs across rollovers if
the CPU doesn't have an active ASID when the rollover occurs.

Acked-by: Will Deacon <[email protected]>
Acked-by: Catalin Carinas <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Russell King <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

ARM: 7768/1: prevent risks of out-of-bound access in ASID allocator

commit b8e4a4740fa2b17c0a447b3ab783b3dc10702e27 upstream.

On a CPU that never ran anything, both the active and reserved ASID
fields are set to zero. In this case the ASID_TO_IDX() macro will
return -1, which is not a very useful value to index a bitmap.

Instead of trying to offset the ASID so that ASID lg-devs#1 is actually
bit 0 in the asid_map bitmap, just always ignore bit 0 and start
the search from bit 1. This makes the code a bit more readable,
and without risk of OoB access.

Acked-by: Will Deacon <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Reported-by: Catalin Marinas <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Russell King <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

ARM: 7703/1: Disable preemption in broadcast_tlb*_a15_erratum()

Commit 93dc688 (ARM: 7684/1: errata: Workaround for Cortex-A15 erratum
798181 (TLBI/DSB operations)) introduces calls to smp_processor_id() and
smp_call_function_many() with preemption enabled. This patch disables
preemption and also optimises the smp_processor_id() call in
broadcast_tlb_mm_a15_erratum(). The broadcast_tlb_a15_erratum() function
is changed to use smp_call_function() which disables preemption.

Signed-off-by: Catalin Marinas <[email protected]>
Reported-by: Geoff Levand <[email protected]>
Reported-by: Nicolas Pitre <[email protected]>
Signed-off-by: Russell King <[email protected]>

ARM: 7769/1: Cortex-A15: fix erratum 798181 implementation

commit 0d0752bca1f9a91fb646647aa4abbb21156f316c upstream.

Looking into the active_asids array is not enough, as we also need
to look into the reserved_asids array (they both represent processes
that are currently running).

Also, not holding the ASID allocator lock is racy, as another CPU
could schedule that process and trigger a rollover, making the erratum
workaround miss an IPI.

Exposing this outside of context.c is a little ugly on the side, so
let's define a new entry point that the erratum workaround can call
to obtain the cpumask.

Acked-by: Will Deacon <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Russell King <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

arm: mm: Clean ASID patchset

Change-Id: Id5b0cc6d5300d293e33baf6603453bde0df6d6d8

android/lowmemorykiller: Ignore tasks with freed mm

A killed task can stay in the task list long after its
memory has been returned to the system, therefore
ignore any tasks whose mm struct has been freed.

Change-Id: I76394b203b4ab2312437c839976f0ecb7b6dde4e
CRs-fixed: 450383
Signed-off-by: Liam Mark <[email protected]>
Signed-off-by: Pranav Vashi <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Aug 13, 2015
While running hotplug tests I ran into this RCU splat

===============================
[ INFO: suspicious RCU usage. ]
3.4.0 #3275 Tainted: G        W
-------------------------------
include/linux/rcupdate.h:729 rcu_read_lock() used illegally while idle!

other info that might help us debug this:

RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
4 locks held by swapper/2/0:
 #0:  ((cpu_died).wait.lock){......}, at: [<c00ab128>] complete+0x1c/0x5c
 lg-devs#1:  (&p->pi_lock){-.-.-.}, at: [<c00b275c>] try_to_wake_up+0x2c/0x388
 lg-devs#2:  (&rq->lock){-.-.-.}, at: [<c00b2860>] try_to_wake_up+0x130/0x388
 lg-devs#3:  (rcu_read_lock){.+.+..}, at: [<c00abe5c>] cpuacct_charge+0x28/0x1f4

stack backtrace:
[<c001521c>] (unwind_backtrace+0x0/0x12c) from [<c00abec8>] (cpuacct_charge+0x94/0x1f4)
[<c00abec8>] (cpuacct_charge+0x94/0x1f4) from [<c00b395c>] (update_curr+0x24c/0x2c8)
[<c00b395c>] (update_curr+0x24c/0x2c8) from [<c00b59c4>] (enqueue_task_fair+0x50/0x194)
[<c00b59c4>] (enqueue_task_fair+0x50/0x194) from [<c00afea4>] (enqueue_task+0x30/0x34)
[<c00afea4>] (enqueue_task+0x30/0x34) from [<c00b0908>] (ttwu_activate+0x14/0x38)
[<c00b0908>] (ttwu_activate+0x14/0x38) from [<c00b28a8>] (try_to_wake_up+0x178/0x388)
[<c00b28a8>] (try_to_wake_up+0x178/0x388) from [<c00a82a0>] (__wake_up_common+0x34/0x78)
[<c00a82a0>] (__wake_up_common+0x34/0x78) from [<c00ab154>] (complete+0x48/0x5c)
[<c00ab154>] (complete+0x48/0x5c) from [<c07db7cc>] (cpu_die+0x2c/0x58)
[<c07db7cc>] (cpu_die+0x2c/0x58) from [<c000f954>] (cpu_idle+0x64/0xfc)
[<c000f954>] (cpu_idle+0x64/0xfc) from [<80208160>] (0x80208160)

When a cpu is marked offline during its idle thread it calls
cpu_die() during an RCU idle period. cpu_die() calls complete()
to notify the killing process that the cpu has died. complete()
calls into the scheduler code and eventually grabs an RCU read
lock in cpuacct_charge().

Mark complete() as RCU_NONIDLE so that RCU pays attention to this
CPU for the duration of the complete() function even though it's
in idle.

Change-Id: I548a278e595737390bbc2c97bddda06a0725ecbd
Suggested-by: "Paul E. McKenney" <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Nov 5, 2016
Fix a short sprintf buffer in proc_keys_show().  If the gcc stack protector
is turned on, this can cause a panic due to stack corruption.

The problem is that xbuf[] is not big enough to hold a 64-bit timeout
rendered as weeks:

	(gdb) p 0xffffffffffffffffULL/(60*60*24*7)
	$2 = 30500568904943

That's 14 chars plus NUL, not 11 chars plus NUL.

Expand the buffer to 16 chars.

I think the unpatched code apparently works if the stack-protector is not
enabled because on a 32-bit machine the buffer won't be overflowed and on a
64-bit machine there's a 64-bit aligned pointer at one side and an int that
isn't checked again on the other side.

The panic incurred looks something like:

Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff81352ebe
CPU: 0 PID: 1692 Comm: reproducer Not tainted 4.7.2-201.fc24.x86_64 lg-devs#1
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
 0000000000000086 00000000fbbd2679 ffff8800a044bc00 ffffffff813d941f
 ffffffff81a28d58 ffff8800a044bc98 ffff8800a044bc88 ffffffff811b2cb6
 ffff880000000010 ffff8800a044bc98 ffff8800a044bc30 00000000fbbd2679
Call Trace:
 [<ffffffff813d941f>] dump_stack+0x63/0x84
 [<ffffffff811b2cb6>] panic+0xde/0x22a
 [<ffffffff81352ebe>] ? proc_keys_show+0x3ce/0x3d0
 [<ffffffff8109f7f9>] __stack_chk_fail+0x19/0x30
 [<ffffffff81352ebe>] proc_keys_show+0x3ce/0x3d0
 [<ffffffff81350410>] ? key_validate+0x50/0x50
 [<ffffffff8134db30>] ? key_default_cmp+0x20/0x20
 [<ffffffff8126b31c>] seq_read+0x2cc/0x390
 [<ffffffff812b6b12>] proc_reg_read+0x42/0x70
 [<ffffffff81244fc7>] __vfs_read+0x37/0x150
 [<ffffffff81357020>] ? security_file_permission+0xa0/0xc0
 [<ffffffff81246156>] vfs_read+0x96/0x130
 [<ffffffff81247635>] SyS_read+0x55/0xc0
 [<ffffffff817eb872>] entry_SYSCALL_64_fastpath+0x1a/0xa4

Change-Id: I0787d5a38c730ecb75d3c08f28f0ab36295d59e7
Reported-by: Ondrej Kozina <[email protected]>
Signed-off-by: David Howells <[email protected]>
Tested-by: Ondrej Kozina <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Nov 5, 2016
Once we failed to merge inline data into inode page during flushing inline
inode, we will skip invoking inode_dec_dirty_pages, which makes dirty page
count incorrect, result in panic in ->evict_inode, Fix it.

------------[ cut here ]------------
kernel BUG at /home/yuchao/git/devf2fs/inode.c:336!
invalid opcode: 0000 [lg-devs#1] PREEMPT SMP
CPU: 3 PID: 10004 Comm: umount Tainted: G           O    4.6.0-rc5+ lg-devs#17
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
task: f0c33000 ti: c5212000 task.ti: c5212000
EIP: 0060:[<f89aacb5>] EFLAGS: 00010202 CPU: 3
EIP is at f2fs_evict_inode+0x85/0x490 [f2fs]
EAX: 00000001 EBX: c4529ea0 ECX: 00000001 EDX: 00000000
ESI: c0131000 EDI: f89dd0a0 EBP: c5213e9c ESP: c5213e7
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
CR0: 80050033 CR2: b75878c0 CR3: 1a36a700 CR4: 000406f0
Stack:
 c4529ea0 c4529ef4 c5213e8c c176d45c c4529ef4 00000000 c4529ea0 c4529fac
 f89dd0a0 c5213eb0 c1204a68 c5213ed8 c452a2b4 c6680930 c5213ec0 c1204b64
 c6680d44 c6680620 c5213eec c120588d ee84b000 ee84b5c0 c5214000 ee84b5e0
Call Trace:
 [<c176d45c>] ? _raw_spin_unlock+0x2c/0x50
 [<c1204a68>] evict+0xa8/0x170
 [<c1204b64>] dispose_list+0x34/0x50
 [<c120588d>] evict_inodes+0x10d/0x130
 [<c11ea941>] generic_shutdown_super+0x41/0xe0
 [<c1185190>] ? unregister_shrinker+0x40/0x50
 [<c1185190>] ? unregister_shrinker+0x40/0x50
 [<c11eac52>] kill_block_super+0x22/0x70
 [<f89af23e>] kill_f2fs_super+0x1e/0x20 [f2fs]
 [<c11eae1d>] deactivate_locked_super+0x3d/0x70
 [<c11eb383>] deactivate_super+0x43/0x60
 [<c1208ec9>] cleanup_mnt+0x39/0x80
 [<c1208f50>] __cleanup_mnt+0x10/0x20
 [<c107d091>] task_work_run+0x71/0x90
 [<c105725a>] exit_to_usermode_loop+0x72/0x9e
 [<c1001c7c>] do_fast_syscall_32+0x19c/0x1c0
 [<c176dd48>] sysenter_past_esp+0x45/0x74
EIP: [<f89aacb5>] f2fs_evict_inode+0x85/0x490 [f2fs] SS:ESP 0068:c5213e78
---[ end trace d30536330b7fdc58 ]---

Signed-off-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>

Change-Id: Iad209ae94828e8e38955459d1ea9573c9e11ede6
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Nov 5, 2016
Fix a short sprintf buffer in proc_keys_show().  If the gcc stack protector
is turned on, this can cause a panic due to stack corruption.

The problem is that xbuf[] is not big enough to hold a 64-bit timeout
rendered as weeks:

	(gdb) p 0xffffffffffffffffULL/(60*60*24*7)
	$2 = 30500568904943

That's 14 chars plus NUL, not 11 chars plus NUL.

Expand the buffer to 16 chars.

I think the unpatched code apparently works if the stack-protector is not
enabled because on a 32-bit machine the buffer won't be overflowed and on a
64-bit machine there's a 64-bit aligned pointer at one side and an int that
isn't checked again on the other side.

The panic incurred looks something like:

Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff81352ebe
CPU: 0 PID: 1692 Comm: reproducer Not tainted 4.7.2-201.fc24.x86_64 lg-devs#1
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
 0000000000000086 00000000fbbd2679 ffff8800a044bc00 ffffffff813d941f
 ffffffff81a28d58 ffff8800a044bc98 ffff8800a044bc88 ffffffff811b2cb6
 ffff880000000010 ffff8800a044bc98 ffff8800a044bc30 00000000fbbd2679
Call Trace:
 [<ffffffff813d941f>] dump_stack+0x63/0x84
 [<ffffffff811b2cb6>] panic+0xde/0x22a
 [<ffffffff81352ebe>] ? proc_keys_show+0x3ce/0x3d0
 [<ffffffff8109f7f9>] __stack_chk_fail+0x19/0x30
 [<ffffffff81352ebe>] proc_keys_show+0x3ce/0x3d0
 [<ffffffff81350410>] ? key_validate+0x50/0x50
 [<ffffffff8134db30>] ? key_default_cmp+0x20/0x20
 [<ffffffff8126b31c>] seq_read+0x2cc/0x390
 [<ffffffff812b6b12>] proc_reg_read+0x42/0x70
 [<ffffffff81244fc7>] __vfs_read+0x37/0x150
 [<ffffffff81357020>] ? security_file_permission+0xa0/0xc0
 [<ffffffff81246156>] vfs_read+0x96/0x130
 [<ffffffff81247635>] SyS_read+0x55/0xc0
 [<ffffffff817eb872>] entry_SYSCALL_64_fastpath+0x1a/0xa4

Change-Id: I0787d5a38c730ecb75d3c08f28f0ab36295d59e7
Reported-by: Ondrej Kozina <[email protected]>
Signed-off-by: David Howells <[email protected]>
Tested-by: Ondrej Kozina <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Nov 5, 2016
commit 1b8e6a01e19f001e9f93b39c32387961c91ed3cc upstream.

When a passive TCP is created, we eventually call tcp_md5_do_add()
with sk pointing to the child. It is not owner by the user yet (we
will add this socket into listener accept queue a bit later anyway)

But we do own the spinlock, so amend the lockdep annotation to avoid
following splat :

[ 8451.090932] net/ipv4/tcp_ipv4.c:923 suspicious rcu_dereference_protected() usage!
[ 8451.090932]
[ 8451.090932] other info that might help us debug this:
[ 8451.090932]
[ 8451.090934]
[ 8451.090934] rcu_scheduler_active = 1, debug_locks = 1
[ 8451.090936] 3 locks held by socket_sockopt_/214795:
[ 8451.090936]  #0:  (rcu_read_lock){.+.+..}, at: [<ffffffff855c6ac1>] __netif_receive_skb_core+0x151/0xe90
[ 8451.090947]  lg-devs#1:  (rcu_read_lock){.+.+..}, at: [<ffffffff85618143>] ip_local_deliver_finish+0x43/0x2b0
[ 8451.090952]  lg-devs#2:  (slock-AF_INET){+.-...}, at: [<ffffffff855acda5>] sk_clone_lock+0x1c5/0x500
[ 8451.090958]
[ 8451.090958] stack backtrace:
[ 8451.090960] CPU: 7 PID: 214795 Comm: socket_sockopt_

[ 8451.091215] Call Trace:
[ 8451.091216]  <IRQ>  [<ffffffff856fb29c>] dump_stack+0x55/0x76
[ 8451.091229]  [<ffffffff85123b5b>] lockdep_rcu_suspicious+0xeb/0x110
[ 8451.091235]  [<ffffffff8564544f>] tcp_md5_do_add+0x1bf/0x1e0
[ 8451.091239]  [<ffffffff85645751>] tcp_v4_syn_recv_sock+0x1f1/0x4c0
[ 8451.091242]  [<ffffffff85642b27>] ? tcp_v4_md5_hash_skb+0x167/0x190
[ 8451.091246]  [<ffffffff85647c78>] tcp_check_req+0x3c8/0x500
[ 8451.091249]  [<ffffffff856451ae>] ? tcp_v4_inbound_md5_hash+0x11e/0x190
[ 8451.091253]  [<ffffffff85647170>] tcp_v4_rcv+0x3c0/0x9f0
[ 8451.091256]  [<ffffffff85618143>] ? ip_local_deliver_finish+0x43/0x2b0
[ 8451.091260]  [<ffffffff856181b6>] ip_local_deliver_finish+0xb6/0x2b0
[ 8451.091263]  [<ffffffff85618143>] ? ip_local_deliver_finish+0x43/0x2b0
[ 8451.091267]  [<ffffffff85618d38>] ip_local_deliver+0x48/0x80
[ 8451.091270]  [<ffffffff85618510>] ip_rcv_finish+0x160/0x700
[ 8451.091273]  [<ffffffff8561900e>] ip_rcv+0x29e/0x3d0
[ 8451.091277]  [<ffffffff855c74b7>] __netif_receive_skb_core+0xb47/0xe90

Fixes: a8afca0 ("tcp: md5: protects md5sig_info with RCU")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Willem de Bruijn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Zefan Li <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Nov 5, 2016
commit 19cd80a214821f4b558560ebd76bfb2c38b4f3d8 upstream.

It is not permitted to set task state before lock. usblp_wwait sets
the state to TASK_INTERRUPTIBLE and calls mutex_lock_interruptible.
Upon return from that function, the state will be TASK_RUNNING again.

This is clearly a bug and a warning is generated with LOCKDEP too:
WARNING: CPU: 1 PID: 5109 at kernel/sched/core.c:7404 __might_sleep+0x7d/0x90()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffffa0c588d0>] usblp_wwait+0xa0/0x310 [usblp]
Modules linked in: ...
CPU: 1 PID: 5109 Comm: captmon Tainted: G        W       4.2.5-0.gef2823b-default lg-devs#1
Hardware name: LENOVO 23252SG/23252SG, BIOS G2ET33WW (1.13 ) 07/24/2012
 ffffffff81a4edce ffff880236ec7ba8 ffffffff81716651 0000000000000000
 ffff880236ec7bf8 ffff880236ec7be8 ffffffff8106e146 0000000000000282
 ffffffff81a50119 000000000000028b 0000000000000000 ffff8802dab7c508
Call Trace:
...
 [<ffffffff8106e1c6>] warn_slowpath_fmt+0x46/0x50
 [<ffffffff8109a8bd>] __might_sleep+0x7d/0x90
 [<ffffffff8171b20f>] mutex_lock_interruptible_nested+0x2f/0x4b0
 [<ffffffffa0c588fc>] usblp_wwait+0xcc/0x310 [usblp]
 [<ffffffffa0c58bb2>] usblp_write+0x72/0x350 [usblp]
 [<ffffffff8121ed98>] __vfs_write+0x28/0xf0
...

Commit 7f47735 (usblp: Implement the
ENOSPC convention) moved the set prior locking. So move it back after
the lock.

Signed-off-by: Jiri Slaby <[email protected]>
Fixes: 7f47735 ("usblp: Implement the ENOSPC convention")
Acked-By: Pete Zaitcev <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Zefan Li <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Nov 5, 2016
commit 9ce119f318ba1a07c29149301f1544b6c4bea52a upstream.

A line discipline which does not define a receive_buf() method can
can cause a GPF if data is ever received [1]. Oddly, this was known
to the author of n_tracesink in 2011, but never fixed.

[1] GPF report
    BUG: unable to handle kernel NULL pointer dereference at           (null)
    IP: [<          (null)>]           (null)
    PGD 3752d067 PUD 37a7b067 PMD 0
    Oops: 0010 [lg-devs#1] SMP KASAN
    Modules linked in:
    CPU: 2 PID: 148 Comm: kworker/u10:2 Not tainted 4.4.0-rc2+ #51
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    Workqueue: events_unbound flush_to_ldisc
    task: ffff88006da94440 ti: ffff88006db60000 task.ti: ffff88006db60000
    RIP: 0010:[<0000000000000000>]  [<          (null)>]           (null)
    RSP: 0018:ffff88006db67b50  EFLAGS: 00010246
    RAX: 0000000000000102 RBX: ffff88003ab32f88 RCX: 0000000000000102
    RDX: 0000000000000000 RSI: ffff88003ab330a6 RDI: ffff88003aabd388
    RBP: ffff88006db67c48 R08: ffff88003ab32f9c R09: ffff88003ab31fb0
    R10: ffff88003ab32fa8 R11: 0000000000000000 R12: dffffc0000000000
    R13: ffff88006db67c20 R14: ffffffff863df820 R15: ffff88003ab31fb8
    FS:  0000000000000000(0000) GS:ffff88006dc00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
    CR2: 0000000000000000 CR3: 0000000037938000 CR4: 00000000000006e0
    Stack:
     ffffffff829f46f1 ffff88006da94bf8 ffff88006da94bf8 0000000000000000
     ffff88003ab31fb0 ffff88003aabd438 ffff88003ab31ff8 ffff88006430fd90
     ffff88003ab32f9c ffffed0007557a87 1ffff1000db6cf78 ffff88003ab32078
    Call Trace:
     [<ffffffff8127cf91>] process_one_work+0x8f1/0x17a0 kernel/workqueue.c:2030
     [<ffffffff8127df14>] worker_thread+0xd4/0x1180 kernel/workqueue.c:2162
     [<ffffffff8128faaf>] kthread+0x1cf/0x270 drivers/block/aoe/aoecmd.c:1302
     [<ffffffff852a7c2f>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
    Code:  Bad RIP value.
    RIP  [<          (null)>]           (null)
     RSP <ffff88006db67b50>
    CR2: 0000000000000000
    ---[ end trace a587f8947e54d6ea ]---

Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
[lizf: Backportd to 3.4: adjust context]
Signed-off-by: Zefan Li <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Nov 5, 2016
commit 7f98ca454ad373fc1b76be804fa7138ff68c1d27 upstream.

We apparantly get a hotplug irq before we've initialised
modesetting,

[drm] Loading R100 Microcode
BUG: unable to handle kernel NULL pointer dereference at   (null)
IP: [<c125f56f>] __mutex_lock_slowpath+0x23/0x91
*pde = 00000000
Oops: 0002 [lg-devs#1]
Modules linked in: radeon(+) drm_kms_helper ttm drm i2c_algo_bit backlight pcspkr psmouse evdev sr_mod input_leds led_class cdrom sg parport_pc parport floppy intel_agp intel_gtt lpc_ich acpi_cpufreq processor button mfd_core agpgart uhci_hcd ehci_hcd rng_core snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm usbcore usb_common i2c_i801 i2c_core snd_timer snd soundcore thermal_sys
CPU: 0 PID: 15 Comm: kworker/0:1 Not tainted 4.2.0-rc7-00015-gbf67402 #111
Hardware name: MicroLink                               /D850MV                         , BIOS MV85010A.86A.0067.P24.0304081124 04/08/2003
Workqueue: events radeon_hotplug_work_func [radeon]
task: f6ca5900 ti: f6d3e000 task.ti: f6d3e000
EIP: 0060:[<c125f56f>] EFLAGS: 00010282 CPU: 0
EIP is at __mutex_lock_slowpath+0x23/0x91
EAX: 00000000 EBX: f5e900fc ECX: 00000000 EDX: fffffffe
ESI: f6ca5900 EDI: f5e90100 EBP: f5e90000 ESP: f6d3ff0c
 DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068
CR0: 8005003b CR2: 00000000 CR3: 36f61000 CR4: 000006d0
Stack:
 f5e90100 00000000 c103c4c1 f6d2a5a0 f5e900fc f6df394c c125f162 f8b0faca
 f6d2a5a0 c138ca00 f6df394c f7395600 c1034741 00d40000 00000000 f6d2a5a0
 c138ca00 f6d2a5b8 c138ca10 c1034b58 00000001 f6d40000 f6ca5900 f6d0c940
Call Trace:
 [<c103c4c1>] ? dequeue_task_fair+0xa4/0xb7
 [<c125f162>] ? mutex_lock+0x9/0xa
 [<f8b0faca>] ? radeon_hotplug_work_func+0x17/0x57 [radeon]
 [<c1034741>] ? process_one_work+0xfc/0x194
 [<c1034b58>] ? worker_thread+0x18d/0x218
 [<c10349cb>] ? rescuer_thread+0x1d5/0x1d5
 [<c103742a>] ? kthread+0x7b/0x80
 [<c12601c0>] ? ret_from_kernel_thread+0x20/0x30
 [<c10373af>] ? init_completion+0x18/0x18
Code: 42 08 e8 8e a6 dd ff c3 57 56 53 83 ec 0c 8b 35 48 f7 37 c1 8b 10 4a 74 1a 89 c3 8d 78 04 8b 40 08 89 63

Reported-and-Tested-by: Meelis Roos <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>
Cc: Ben Hutchings <[email protected]>
Signed-off-by: Zefan Li <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Nov 5, 2016
…ut event

commit 635682a14427d241bab7bbdeebb48a7d7b91638e upstream.

A case can occur when sctp_accept() is called by the user during
a heartbeat timeout event after the 4-way handshake.  Since
sctp_assoc_migrate() changes both assoc->base.sk and assoc->ep, the
bh_sock_lock in sctp_generate_heartbeat_event() will be taken with
the listening socket but released with the new association socket.
The result is a deadlock on any future attempts to take the listening
socket lock.

Note that this race can occur with other SCTP timeouts that take
the bh_lock_sock() in the event sctp_accept() is called.

 BUG: soft lockup - CPU#9 stuck for 67s! [swapper:0]
 ...
 RIP: 0010:[<ffffffff8152d48e>]  [<ffffffff8152d48e>] _spin_lock+0x1e/0x30
 RSP: 0018:ffff880028323b20  EFLAGS: 00000206
 RAX: 0000000000000002 RBX: ffff880028323b20 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: ffff880028323be0 RDI: ffff8804632c4b48
 RBP: ffffffff8100bb93 R08: 0000000000000000 R09: 0000000000000000
 R10: ffff880610662280 R11: 0000000000000100 R12: ffff880028323aa0
 R13: ffff8804383c3880 R14: ffff880028323a90 R15: ffffffff81534225
 FS:  0000000000000000(0000) GS:ffff880028320000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
 CR2: 00000000006df528 CR3: 0000000001a85000 CR4: 00000000000006e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Process swapper (pid: 0, threadinfo ffff880616b70000, task ffff880616b6cab0)
 Stack:
 ffff880028323c40 ffffffffa01c2582 ffff880614cfb020 0000000000000000
 <d> 0100000000000000 00000014383a6c44 ffff8804383c3880 ffff880614e93c00
 <d> ffff880614e93c00 0000000000000000 ffff8804632c4b00 ffff8804383c38b8
 Call Trace:
 <IRQ>
 [<ffffffffa01c2582>] ? sctp_rcv+0x492/0xa10 [sctp]
 [<ffffffff8148c559>] ? nf_iterate+0x69/0xb0
 [<ffffffff814974a0>] ? ip_local_deliver_finish+0x0/0x2d0
 [<ffffffff8148c716>] ? nf_hook_slow+0x76/0x120
 [<ffffffff814974a0>] ? ip_local_deliver_finish+0x0/0x2d0
 [<ffffffff8149757d>] ? ip_local_deliver_finish+0xdd/0x2d0
 [<ffffffff81497808>] ? ip_local_deliver+0x98/0xa0
 [<ffffffff81496ccd>] ? ip_rcv_finish+0x12d/0x440
 [<ffffffff81497255>] ? ip_rcv+0x275/0x350
 [<ffffffff8145cfeb>] ? __netif_receive_skb+0x4ab/0x750
 ...

With lockdep debugging:

 =====================================
 [ BUG: bad unlock balance detected! ]
 -------------------------------------
 CslRx/12087 is trying to release lock (slock-AF_INET) at:
 [<ffffffffa01bcae0>] sctp_generate_timeout_event+0x40/0xe0 [sctp]
 but there are no more locks to release!

 other info that might help us debug this:
 2 locks held by CslRx/12087:
 #0:  (&asoc->timers[i]){+.-...}, at: [<ffffffff8108ce1f>] run_timer_softirq+0x16f/0x3e0
 lg-devs#1:  (slock-AF_INET){+.-...}, at: [<ffffffffa01bcac3>] sctp_generate_timeout_event+0x23/0xe0 [sctp]

Ensure the socket taken is also the same one that is released by
saving a copy of the socket before entering the timeout event
critical section.

Signed-off-by: Karl Heiss <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
[bwh: Backported to 3.2:
 - Net namespaces are not used
 - Keep using sctp_bh_{,un}lock_sock()
 - Adjust context]
Signed-off-by: Ben Hutchings <[email protected]>
Signed-off-by: Zefan Li <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Nov 6, 2016
Implement Samsung's FMODE_NONMAPPABLE flag from
sdcardfs version 2.1.4 as we hit a BUG on ext4:

[   49.655037]@0 Kernel BUG at ffffffc0001deeec [verbose debug info unavailable]
[   49.655045]@0 Internal error: Oops - BUG: 0 [lg-devs#1] PREEMPT SMP
[   49.655052]@0 Modules linked in:
[   49.655061]@0 CPU: 0 PID: 283 Comm: kworker/u8:7 Tainted: G        W      3.18.20-perf-g3be2054-00086-ga8307fb lg-devs#1
[   49.655070]@0 Hardware name: Qualcomm Technologies, Inc. MSM 8996 v3 + PMI8996 MTP (DT)
[   49.655077]@0 Workqueue: writeback bdi_writeback_workfn (flush-8:0)
[   49.655096]@0 task: ffffffc174ba8b00 ti: ffffffc174bb4000 task.ti: ffffffc174bb4000
[   49.655108]@0 PC is at mpage_prepare_extent_to_map+0x198/0x218
[   49.655116]@0 LR is at mpage_prepare_extent_to_map+0x110/0x218
[   49.655121]@0 pc : [<ffffffc0001deeec>] lr : [<ffffffc0001dee64>] pstate: 60000145
[   49.655126]@0 sp : ffffffc174bb7800
[   49.655130]@0 x29: ffffffc174bb7800 x28: ffffffc174bb7880
[   49.655140]@0 x27: 000000000000000d x26: ffffffc1245505e8
[   49.655149]@0 x25: 0000000000000000 x24: 0000000000003400
[   49.655160]@0 x23: ffffffffffffffff x22: 0000000000000000
[   49.655172]@0 x21: ffffffc174bb7888 x20: ffffffc174bb79e0
[   49.655182]@0 x19: ffffffbdc4ee7b80 x18: 0000007f92872000
[   49.655191]@0 x17: 0000007f959b6424 x16: ffffffc00016d1ac
[   49.655201]@0 x15: 0000007f9285d158 x14: ffffffc1734796e8
[   49.655210]@0 x13: ffffffbdc1ffa4c0 x12: ffffffbdc4ee7b80
[   49.655220]@0 x11: 0000000000000100 x10: 0000000000000000
[   49.655229]@0 x9 : 0000000000000000 x8 : ffffffc0b444e210
[   49.655237]@0 x7 : 0000000000000000 x6 : ffffffc0b444e1e0
[   49.655246]@0 x5 : 0000000000000000 x4 : 0000000000000001
[   49.655254]@0 x3 : 0000000000000000 x2 : 400000000002003d
[   49.655263]@0 x1 : ffffffbdc4ee7b80 x0 : 400000000002003d
[   49.655271]@0
[   49.656502]@0 Process kworker/u8:7 (pid: 283, stack limit = 0xffffffc174bb4058)
[   49.656509]@0 Call trace:
[   49.656514]@0 [<ffffffc0001deeec>] mpage_prepare_extent_to_map+0x198/0x218
[   49.656526]@0 [<ffffffc0001e28d0>] ext4_writepages+0x270/0xa58
[   49.656533]@0 [<ffffffc00012982c>] do_writepages+0x24/0x40
[   49.656541]@0 [<ffffffc000180160>] __writeback_single_inode+0x40/0x114
[   49.656549]@0 [<ffffffc000180e50>] writeback_sb_inodes+0x1dc/0x34c
[   49.656555]@0 [<ffffffc00018103c>] __writeback_inodes_wb+0x7c/0xc4
[   49.656560]@0 [<ffffffc000181224>] wb_writeback+0x110/0x1a8
[   49.656565]@0 [<ffffffc000181344>] wb_check_old_data_flush+0x88/0x98
[   49.656571]@0 [<ffffffc00018156c>] bdi_writeback_workfn+0xf4/0x1fc
[   49.656576]@0 [<ffffffc0000b14f8>] process_one_work+0x1e0/0x300
[   49.656585]@0 [<ffffffc0000b1e14>] worker_thread+0x318/0x438
[   49.656590]@0 [<ffffffc0000b5da0>] kthread+0xe0/0xec
[   49.656598]@0 Code: f9400260 f9400a63 1ad92063 37580040 (e7f001f2)
[   49.656604]@0 ---[ end trace cbed09f772fd630d ]---

Change-Id: I931da7cb3841db1f130dba298a7d256b6f02d1bc
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Nov 26, 2016
bfq maintains a 'next-in-service' cache to prevent expensive lookups in
the hot path. However, the cache sometimes becomes inconsistent and
triggers a BUG:

[44042.622839] -(3)[154:mmcqd/0]BUG: failure at ../../../../../../kernel/cyanogen/mt6735/block/bfq-sched.c:72/bfq_check_next_in_service()!
[44042.622858] -(3)[154:mmcqd/0]Unable to handle kernel paging request at virtual address 0000dead
[44042.622866] -(3)[154:mmcqd/0]pgd = ffffffc001361000
[44042.622872] [0000dead] *pgd=000000007d816003, *pud=000000007d816003, *pmd=000000007d817003, *pte=0000000000000000
[44042.622890] -(3)[154:mmcqd/0]Internal error: Oops: 96000045 [lg-devs#1] PREEMPT SMP
[44042.622907] -(3)[154:mmcqd/0]CPU: 3 PID: 154 Comm: mmcqd/0 Tainted:
[44042.622915] -(3)[154:mmcqd/0]Hardware name: MT6735 (DT)
[44042.622922] -(3)[154:mmcqd/0]task: ffffffc0378a6000 ti: ffffffc0378c4000
[44042.622936] -(3)[154:mmcqd/0]PC is at bfq_dispatch_requests+0x6c4/0x9bc
[44042.622944] -(3)[154:mmcqd/0]LR is at bfq_dispatch_requests+0x6bc/0x9bc
[44042.622952] -(3)[154:mmcqd/0]pc : [<ffffffc000306a68>] lr : [<ffffffc000306a60>] pstate: 800001c5
[44042.622958] -(3)[154:mmcqd/0]sp : ffffffc0378c7d30
[44042.622962] x29: ffffffc0378c7d30 x28: 0000000000000000
[44042.622972] x27: 0000000000000000 x26: ffffffc006c58810
[44042.622981] x25: ffffffc037f89820 x24: ffffffc000f14000
[44042.622990] x23: ffffffc036adb088 x22: ffffffc0369b2800
[44042.623000] x21: ffffffc036adb098 x20: ffffffc01d6a3b60
[44042.623009] x19: ffffffc036adb0c8 x18: 0000007f8cfa1500
[44042.623018] x17: 0000007f8db44f40 x16: ffffffc00012d0c0
[44042.623027] x15: 0000007f8dde04d8 x14: 676f6e6179632f6c
[44042.623037] x13: 656e72656b2f2e2e x12: 2f2e2e2f2e2e2f2e
[44042.623046] x11: 2e2f2e2e2f2e2e20 x10: 7461206572756c69
[44042.623055] x9 : 6166203a4755425d x8 : 00000000001f0cc5
[44042.623064] x7 : ffffffc000f3d5a0 x6 : 000000000000008b
[44042.623073] x5 : 0000000000000000 x4 : 0000000000000004
[44042.623082] x3 : 0000000000000002 x2 : 0000000000000001
[44042.623091] x1 : 0000000000000aee x0 : 000000000000dead

This patch makes the lookup resilient to cache inconsistencies by doing
the expensive recomputation in cases where the bug would otherwise be
triggered.

Ticket: PORRDIGE-527

Change-Id: I5dd701960057983a42d3d3bd57521e8d17c03d7f
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Nov 27, 2016
Fix a short sprintf buffer in proc_keys_show().  If the gcc stack protector
is turned on, this can cause a panic due to stack corruption.

The problem is that xbuf[] is not big enough to hold a 64-bit timeout
rendered as weeks:

	(gdb) p 0xffffffffffffffffULL/(60*60*24*7)
	$2 = 30500568904943

That's 14 chars plus NUL, not 11 chars plus NUL.

Expand the buffer to 16 chars.

I think the unpatched code apparently works if the stack-protector is not
enabled because on a 32-bit machine the buffer won't be overflowed and on a
64-bit machine there's a 64-bit aligned pointer at one side and an int that
isn't checked again on the other side.

The panic incurred looks something like:

Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff81352ebe
CPU: 0 PID: 1692 Comm: reproducer Not tainted 4.7.2-201.fc24.x86_64 lg-devs#1
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
 0000000000000086 00000000fbbd2679 ffff8800a044bc00 ffffffff813d941f
 ffffffff81a28d58 ffff8800a044bc98 ffff8800a044bc88 ffffffff811b2cb6
 ffff880000000010 ffff8800a044bc98 ffff8800a044bc30 00000000fbbd2679
Call Trace:
 [<ffffffff813d941f>] dump_stack+0x63/0x84
 [<ffffffff811b2cb6>] panic+0xde/0x22a
 [<ffffffff81352ebe>] ? proc_keys_show+0x3ce/0x3d0
 [<ffffffff8109f7f9>] __stack_chk_fail+0x19/0x30
 [<ffffffff81352ebe>] proc_keys_show+0x3ce/0x3d0
 [<ffffffff81350410>] ? key_validate+0x50/0x50
 [<ffffffff8134db30>] ? key_default_cmp+0x20/0x20
 [<ffffffff8126b31c>] seq_read+0x2cc/0x390
 [<ffffffff812b6b12>] proc_reg_read+0x42/0x70
 [<ffffffff81244fc7>] __vfs_read+0x37/0x150
 [<ffffffff81357020>] ? security_file_permission+0xa0/0xc0
 [<ffffffff81246156>] vfs_read+0x96/0x130
 [<ffffffff81247635>] SyS_read+0x55/0xc0
 [<ffffffff817eb872>] entry_SYSCALL_64_fastpath+0x1a/0xa4

Change-Id: I0787d5a38c730ecb75d3c08f28f0ab36295d59e7
Reported-by: Ondrej Kozina <[email protected]>
Signed-off-by: David Howells <[email protected]>
Tested-by: Ondrej Kozina <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Nov 27, 2016
Implement Samsung's FMODE_NONMAPPABLE flag from
sdcardfs version 2.1.4 as we hit a BUG on ext4:

[   49.655037]@0 Kernel BUG at ffffffc0001deeec [verbose debug info unavailable]
[   49.655045]@0 Internal error: Oops - BUG: 0 [lg-devs#1] PREEMPT SMP
[   49.655052]@0 Modules linked in:
[   49.655061]@0 CPU: 0 PID: 283 Comm: kworker/u8:7 Tainted: G        W      3.18.20-perf-g3be2054-00086-ga8307fb lg-devs#1
[   49.655070]@0 Hardware name: Qualcomm Technologies, Inc. MSM 8996 v3 + PMI8996 MTP (DT)
[   49.655077]@0 Workqueue: writeback bdi_writeback_workfn (flush-8:0)
[   49.655096]@0 task: ffffffc174ba8b00 ti: ffffffc174bb4000 task.ti: ffffffc174bb4000
[   49.655108]@0 PC is at mpage_prepare_extent_to_map+0x198/0x218
[   49.655116]@0 LR is at mpage_prepare_extent_to_map+0x110/0x218
[   49.655121]@0 pc : [<ffffffc0001deeec>] lr : [<ffffffc0001dee64>] pstate: 60000145
[   49.655126]@0 sp : ffffffc174bb7800
[   49.655130]@0 x29: ffffffc174bb7800 x28: ffffffc174bb7880
[   49.655140]@0 x27: 000000000000000d x26: ffffffc1245505e8
[   49.655149]@0 x25: 0000000000000000 x24: 0000000000003400
[   49.655160]@0 x23: ffffffffffffffff x22: 0000000000000000
[   49.655172]@0 x21: ffffffc174bb7888 x20: ffffffc174bb79e0
[   49.655182]@0 x19: ffffffbdc4ee7b80 x18: 0000007f92872000
[   49.655191]@0 x17: 0000007f959b6424 x16: ffffffc00016d1ac
[   49.655201]@0 x15: 0000007f9285d158 x14: ffffffc1734796e8
[   49.655210]@0 x13: ffffffbdc1ffa4c0 x12: ffffffbdc4ee7b80
[   49.655220]@0 x11: 0000000000000100 x10: 0000000000000000
[   49.655229]@0 x9 : 0000000000000000 x8 : ffffffc0b444e210
[   49.655237]@0 x7 : 0000000000000000 x6 : ffffffc0b444e1e0
[   49.655246]@0 x5 : 0000000000000000 x4 : 0000000000000001
[   49.655254]@0 x3 : 0000000000000000 x2 : 400000000002003d
[   49.655263]@0 x1 : ffffffbdc4ee7b80 x0 : 400000000002003d
[   49.655271]@0
[   49.656502]@0 Process kworker/u8:7 (pid: 283, stack limit = 0xffffffc174bb4058)
[   49.656509]@0 Call trace:
[   49.656514]@0 [<ffffffc0001deeec>] mpage_prepare_extent_to_map+0x198/0x218
[   49.656526]@0 [<ffffffc0001e28d0>] ext4_writepages+0x270/0xa58
[   49.656533]@0 [<ffffffc00012982c>] do_writepages+0x24/0x40
[   49.656541]@0 [<ffffffc000180160>] __writeback_single_inode+0x40/0x114
[   49.656549]@0 [<ffffffc000180e50>] writeback_sb_inodes+0x1dc/0x34c
[   49.656555]@0 [<ffffffc00018103c>] __writeback_inodes_wb+0x7c/0xc4
[   49.656560]@0 [<ffffffc000181224>] wb_writeback+0x110/0x1a8
[   49.656565]@0 [<ffffffc000181344>] wb_check_old_data_flush+0x88/0x98
[   49.656571]@0 [<ffffffc00018156c>] bdi_writeback_workfn+0xf4/0x1fc
[   49.656576]@0 [<ffffffc0000b14f8>] process_one_work+0x1e0/0x300
[   49.656585]@0 [<ffffffc0000b1e14>] worker_thread+0x318/0x438
[   49.656590]@0 [<ffffffc0000b5da0>] kthread+0xe0/0xec
[   49.656598]@0 Code: f9400260 f9400a63 1ad92063 37580040 (e7f001f2)
[   49.656604]@0 ---[ end trace cbed09f772fd630d ]---

Change-Id: I931da7cb3841db1f130dba298a7d256b6f02d1bc
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Nov 27, 2016
bfq maintains a 'next-in-service' cache to prevent expensive lookups in
the hot path. However, the cache sometimes becomes inconsistent and
triggers a BUG:

[44042.622839] -(3)[154:mmcqd/0]BUG: failure at ../../../../../../kernel/cyanogen/mt6735/block/bfq-sched.c:72/bfq_check_next_in_service()!
[44042.622858] -(3)[154:mmcqd/0]Unable to handle kernel paging request at virtual address 0000dead
[44042.622866] -(3)[154:mmcqd/0]pgd = ffffffc001361000
[44042.622872] [0000dead] *pgd=000000007d816003, *pud=000000007d816003, *pmd=000000007d817003, *pte=0000000000000000
[44042.622890] -(3)[154:mmcqd/0]Internal error: Oops: 96000045 [lg-devs#1] PREEMPT SMP
[44042.622907] -(3)[154:mmcqd/0]CPU: 3 PID: 154 Comm: mmcqd/0 Tainted:
[44042.622915] -(3)[154:mmcqd/0]Hardware name: MT6735 (DT)
[44042.622922] -(3)[154:mmcqd/0]task: ffffffc0378a6000 ti: ffffffc0378c4000
[44042.622936] -(3)[154:mmcqd/0]PC is at bfq_dispatch_requests+0x6c4/0x9bc
[44042.622944] -(3)[154:mmcqd/0]LR is at bfq_dispatch_requests+0x6bc/0x9bc
[44042.622952] -(3)[154:mmcqd/0]pc : [<ffffffc000306a68>] lr : [<ffffffc000306a60>] pstate: 800001c5
[44042.622958] -(3)[154:mmcqd/0]sp : ffffffc0378c7d30
[44042.622962] x29: ffffffc0378c7d30 x28: 0000000000000000
[44042.622972] x27: 0000000000000000 x26: ffffffc006c58810
[44042.622981] x25: ffffffc037f89820 x24: ffffffc000f14000
[44042.622990] x23: ffffffc036adb088 x22: ffffffc0369b2800
[44042.623000] x21: ffffffc036adb098 x20: ffffffc01d6a3b60
[44042.623009] x19: ffffffc036adb0c8 x18: 0000007f8cfa1500
[44042.623018] x17: 0000007f8db44f40 x16: ffffffc00012d0c0
[44042.623027] x15: 0000007f8dde04d8 x14: 676f6e6179632f6c
[44042.623037] x13: 656e72656b2f2e2e x12: 2f2e2e2f2e2e2f2e
[44042.623046] x11: 2e2f2e2e2f2e2e20 x10: 7461206572756c69
[44042.623055] x9 : 6166203a4755425d x8 : 00000000001f0cc5
[44042.623064] x7 : ffffffc000f3d5a0 x6 : 000000000000008b
[44042.623073] x5 : 0000000000000000 x4 : 0000000000000004
[44042.623082] x3 : 0000000000000002 x2 : 0000000000000001
[44042.623091] x1 : 0000000000000aee x0 : 000000000000dead

This patch makes the lookup resilient to cache inconsistencies by doing
the expensive recomputation in cases where the bug would otherwise be
triggered.

Ticket: PORRDIGE-527

Change-Id: I5dd701960057983a42d3d3bd57521e8d17c03d7f
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Dec 6, 2016
If memory allocation of in pcpu_embed_first_chunk() fails, the
allocated memory is not released correctly. In the release loop also
the non-allocated elements are released which leads to the following
kernel BUG on systems with very little memory:

[    0.000000] kernel BUG at mm/bootmem.c:307!
[    0.000000] illegal operation: 0001 [lg-devs#1] PREEMPT SMP DEBUG_PAGEALLOC
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0 #22
[    0.000000] task: 0000000000a20ae0 ti: 0000000000a08000 task.ti: 0000000000a08000
[    0.000000] Krnl PSW : 0400000180000000 0000000000abda7a (__free+0x116/0x154)
[    0.000000]            R:0 T:1 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 EA:3
...
[    0.000000]  [<0000000000abdce2>] mark_bootmem_node+0xde/0xf0
[    0.000000]  [<0000000000abdd9c>] mark_bootmem+0xa8/0x118
[    0.000000]  [<0000000000abcbba>] pcpu_embed_first_chunk+0xe7a/0xf0c
[    0.000000]  [<0000000000abcc96>] setup_per_cpu_areas+0x4a/0x28c

To fix the problem now only allocated elements are released. This then
leads to the correct kernel panic:

[    0.000000] Kernel panic - not syncing: Failed to initialize percpu areas.
...
[    0.000000] Call Trace:
[    0.000000] ([<000000000011307e>] show_trace+0x132/0x150)
[    0.000000]  [<0000000000113160>] show_stack+0xc4/0xd4
[    0.000000]  [<00000000007127dc>] dump_stack+0x74/0xd8
[    0.000000]  [<00000000007123fe>] panic+0xea/0x264
[    0.000000]  [<0000000000b14814>] setup_per_cpu_areas+0x5c/0x28c

tj: Flipped if conditional so that it doesn't need "continue".

Signed-off-by: Michael Holzheu <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Dec 7, 2016
Beginning at commit d52d3997f843 ("ipv6: Create percpu rt6_info"), the
following INFO splat is logged:

  ===============================
  [ INFO: suspicious RCU usage. ]
  4.1.0-rc7-next-20150612 lg-devs#1 Not tainted
  -------------------------------
  kernel/sched/core.c:7318 Illegal context switch in RCU-bh read-side critical section!
  other info that might help us debug this:
  rcu_scheduler_active = 1, debug_locks = 0
   3 locks held by systemd/1:
   #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff815f0c8f>] rtnetlink_rcv+0x1f/0x40
   lg-devs#1:  (rcu_read_lock_bh){......}, at: [<ffffffff816a34e2>] ipv6_add_addr+0x62/0x540
   lg-devs#2:  (addrconf_hash_lock){+...+.}, at: [<ffffffff816a3604>] ipv6_add_addr+0x184/0x540
  stack backtrace:
  CPU: 0 PID: 1 Comm: systemd Not tainted 4.1.0-rc7-next-20150612 lg-devs#1
  Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.20   04/17/2014
  Call Trace:
    dump_stack+0x4c/0x6e
    lockdep_rcu_suspicious+0xe7/0x120
    ___might_sleep+0x1d5/0x1f0
    __might_sleep+0x4d/0x90
    kmem_cache_alloc+0x47/0x250
    create_object+0x39/0x2e0
    kmemleak_alloc_percpu+0x61/0xe0
    pcpu_alloc+0x370/0x630

Additional backtrace lines are truncated.  In addition, the above splat
is followed by several "BUG: sleeping function called from invalid
context at mm/slub.c:1268" outputs.  As suggested by Martin KaFai Lau,
these are the clue to the fix.  Routine kmemleak_alloc_percpu() always
uses GFP_KERNEL for its allocations, whereas it should follow the gfp
from its callers.

Reviewed-by: Catalin Marinas <[email protected]>
Reviewed-by: Kamalesh Babulal <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
Signed-off-by: Larry Finger <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: <[email protected]>	[3.18+]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Dec 12, 2016
(cherry picked from commit 3d5fe03a3ea013060ebba2a811aeb0f23f56aefa)

We can end up allocating a new compression stream with GFP_KERNEL from
within the IO path, which may result is nested (recursive) IO
operations.  That can introduce problems if the IO path in question is a
reclaimer, holding some locks that will deadlock nested IOs.

Allocate streams and working memory using GFP_NOIO flag, forbidding
recursive IO and FS operations.

An example:

  inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
  git/20158 [HC0[0]:SC0[0]:HE1:SE1] takes:
   (jbd2_handle){+.+.?.}, at:  start_this_handle+0x4ca/0x555
  {IN-RECLAIM_FS-W} state was registered at:
     __lock_acquire+0x8da/0x117b
     lock_acquire+0x10c/0x1a7
     start_this_handle+0x52d/0x555
     jbd2__journal_start+0xb4/0x237
     __ext4_journal_start_sb+0x108/0x17e
     ext4_dirty_inode+0x32/0x61
     __mark_inode_dirty+0x16b/0x60c
     iput+0x11e/0x274
     __dentry_kill+0x148/0x1b8
     shrink_dentry_list+0x274/0x44a
     prune_dcache_sb+0x4a/0x55
     super_cache_scan+0xfc/0x176
     shrink_slab.part.14.constprop.25+0x2a2/0x4d3
     shrink_zone+0x74/0x140
     kswapd+0x6b7/0x930
     kthread+0x107/0x10f
     ret_from_fork+0x3f/0x70
  irq event stamp: 138297
  hardirqs last  enabled at (138297):  debug_check_no_locks_freed+0x113/0x12f
  hardirqs last disabled at (138296):  debug_check_no_locks_freed+0x33/0x12f
  softirqs last  enabled at (137818):  __do_softirq+0x2d3/0x3e9
  softirqs last disabled at (137813):  irq_exit+0x41/0x95

               other info that might help us debug this:
   Possible unsafe locking scenario:
         CPU0
         ----
    lock(jbd2_handle);
    <Interrupt>
      lock(jbd2_handle);

                *** DEADLOCK ***
  5 locks held by git/20158:
   #0:  (sb_writers#7){.+.+.+}, at: [<ffffffff81155411>] mnt_want_write+0x24/0x4b
   lg-devs#1:  (&type->i_mutex_dir_key#2/1){+.+.+.}, at: [<ffffffff81145087>] lock_rename+0xd9/0xe3
   lg-devs#2:  (&sb->s_type->i_mutex_key#11){+.+.+.}, at: [<ffffffff8114f8e2>] lock_two_nondirectories+0x3f/0x6b
   lg-devs#3:  (&sb->s_type->i_mutex_key#11/4){+.+.+.}, at: [<ffffffff8114f909>] lock_two_nondirectories+0x66/0x6b
   lg-devs#4:  (jbd2_handle){+.+.?.}, at: [<ffffffff811e31db>] start_this_handle+0x4ca/0x555

               stack backtrace:
  CPU: 2 PID: 20158 Comm: git Not tainted 4.1.0-rc7-next-20150615-dbg-00016-g8bdf555-dirty #211
  Call Trace:
    dump_stack+0x4c/0x6e
    mark_lock+0x384/0x56d
    mark_held_locks+0x5f/0x76
    lockdep_trace_alloc+0xb2/0xb5
    kmem_cache_alloc_trace+0x32/0x1e2
    zcomp_strm_alloc+0x25/0x73 [zram]
    zcomp_strm_multi_find+0xe7/0x173 [zram]
    zcomp_strm_find+0xc/0xe [zram]
    zram_bvec_rw+0x2ca/0x7e0 [zram]
    zram_make_request+0x1fa/0x301 [zram]
    generic_make_request+0x9c/0xdb
    submit_bio+0xf7/0x120
    ext4_io_submit+0x2e/0x43
    ext4_bio_write_page+0x1b7/0x300
    mpage_submit_page+0x60/0x77
    mpage_map_and_submit_buffers+0x10f/0x21d
    ext4_writepages+0xc8c/0xe1b
    do_writepages+0x23/0x2c
    __filemap_fdatawrite_range+0x84/0x8b
    filemap_flush+0x1c/0x1e
    ext4_alloc_da_blocks+0xb8/0x117
    ext4_rename+0x132/0x6dc
    ? mark_held_locks+0x5f/0x76
    ext4_rename2+0x29/0x2b
    vfs_rename+0x540/0x636
    SyS_renameat2+0x359/0x44d
    SyS_rename+0x1e/0x20
    entry_SYSCALL_64_fastpath+0x12/0x6f

[[email protected]: add stable mark]
Signed-off-by: Sergey Senozhatsky <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Cc: Kyeongdon Kim <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Change-Id: I1ed95ca4937b76634e98b0441c15dd695a43fc62
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Dec 13, 2016
(cherry picked from commit 3d5fe03a3ea013060ebba2a811aeb0f23f56aefa)

We can end up allocating a new compression stream with GFP_KERNEL from
within the IO path, which may result is nested (recursive) IO
operations.  That can introduce problems if the IO path in question is a
reclaimer, holding some locks that will deadlock nested IOs.

Allocate streams and working memory using GFP_NOIO flag, forbidding
recursive IO and FS operations.

An example:

  inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
  git/20158 [HC0[0]:SC0[0]:HE1:SE1] takes:
   (jbd2_handle){+.+.?.}, at:  start_this_handle+0x4ca/0x555
  {IN-RECLAIM_FS-W} state was registered at:
     __lock_acquire+0x8da/0x117b
     lock_acquire+0x10c/0x1a7
     start_this_handle+0x52d/0x555
     jbd2__journal_start+0xb4/0x237
     __ext4_journal_start_sb+0x108/0x17e
     ext4_dirty_inode+0x32/0x61
     __mark_inode_dirty+0x16b/0x60c
     iput+0x11e/0x274
     __dentry_kill+0x148/0x1b8
     shrink_dentry_list+0x274/0x44a
     prune_dcache_sb+0x4a/0x55
     super_cache_scan+0xfc/0x176
     shrink_slab.part.14.constprop.25+0x2a2/0x4d3
     shrink_zone+0x74/0x140
     kswapd+0x6b7/0x930
     kthread+0x107/0x10f
     ret_from_fork+0x3f/0x70
  irq event stamp: 138297
  hardirqs last  enabled at (138297):  debug_check_no_locks_freed+0x113/0x12f
  hardirqs last disabled at (138296):  debug_check_no_locks_freed+0x33/0x12f
  softirqs last  enabled at (137818):  __do_softirq+0x2d3/0x3e9
  softirqs last disabled at (137813):  irq_exit+0x41/0x95

               other info that might help us debug this:
   Possible unsafe locking scenario:
         CPU0
         ----
    lock(jbd2_handle);
    <Interrupt>
      lock(jbd2_handle);

                *** DEADLOCK ***
  5 locks held by git/20158:
   #0:  (sb_writers#7){.+.+.+}, at: [<ffffffff81155411>] mnt_want_write+0x24/0x4b
   lg-devs#1:  (&type->i_mutex_dir_key#2/1){+.+.+.}, at: [<ffffffff81145087>] lock_rename+0xd9/0xe3
   lg-devs#2:  (&sb->s_type->i_mutex_key#11){+.+.+.}, at: [<ffffffff8114f8e2>] lock_two_nondirectories+0x3f/0x6b
   lg-devs#3:  (&sb->s_type->i_mutex_key#11/4){+.+.+.}, at: [<ffffffff8114f909>] lock_two_nondirectories+0x66/0x6b
   lg-devs#4:  (jbd2_handle){+.+.?.}, at: [<ffffffff811e31db>] start_this_handle+0x4ca/0x555

               stack backtrace:
  CPU: 2 PID: 20158 Comm: git Not tainted 4.1.0-rc7-next-20150615-dbg-00016-g8bdf555-dirty #211
  Call Trace:
    dump_stack+0x4c/0x6e
    mark_lock+0x384/0x56d
    mark_held_locks+0x5f/0x76
    lockdep_trace_alloc+0xb2/0xb5
    kmem_cache_alloc_trace+0x32/0x1e2
    zcomp_strm_alloc+0x25/0x73 [zram]
    zcomp_strm_multi_find+0xe7/0x173 [zram]
    zcomp_strm_find+0xc/0xe [zram]
    zram_bvec_rw+0x2ca/0x7e0 [zram]
    zram_make_request+0x1fa/0x301 [zram]
    generic_make_request+0x9c/0xdb
    submit_bio+0xf7/0x120
    ext4_io_submit+0x2e/0x43
    ext4_bio_write_page+0x1b7/0x300
    mpage_submit_page+0x60/0x77
    mpage_map_and_submit_buffers+0x10f/0x21d
    ext4_writepages+0xc8c/0xe1b
    do_writepages+0x23/0x2c
    __filemap_fdatawrite_range+0x84/0x8b
    filemap_flush+0x1c/0x1e
    ext4_alloc_da_blocks+0xb8/0x117
    ext4_rename+0x132/0x6dc
    ? mark_held_locks+0x5f/0x76
    ext4_rename2+0x29/0x2b
    vfs_rename+0x540/0x636
    SyS_renameat2+0x359/0x44d
    SyS_rename+0x1e/0x20
    entry_SYSCALL_64_fastpath+0x12/0x6f

[[email protected]: add stable mark]
Signed-off-by: Sergey Senozhatsky <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Cc: Kyeongdon Kim <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Change-Id: I1ed95ca4937b76634e98b0441c15dd695a43fc62
(cherry picked from commit f19c3ce)
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Dec 21, 2016
(cherry picked from commit 3d5fe03a3ea013060ebba2a811aeb0f23f56aefa)

We can end up allocating a new compression stream with GFP_KERNEL from
within the IO path, which may result is nested (recursive) IO
operations.  That can introduce problems if the IO path in question is a
reclaimer, holding some locks that will deadlock nested IOs.

Allocate streams and working memory using GFP_NOIO flag, forbidding
recursive IO and FS operations.

An example:

  inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
  git/20158 [HC0[0]:SC0[0]:HE1:SE1] takes:
   (jbd2_handle){+.+.?.}, at:  start_this_handle+0x4ca/0x555
  {IN-RECLAIM_FS-W} state was registered at:
     __lock_acquire+0x8da/0x117b
     lock_acquire+0x10c/0x1a7
     start_this_handle+0x52d/0x555
     jbd2__journal_start+0xb4/0x237
     __ext4_journal_start_sb+0x108/0x17e
     ext4_dirty_inode+0x32/0x61
     __mark_inode_dirty+0x16b/0x60c
     iput+0x11e/0x274
     __dentry_kill+0x148/0x1b8
     shrink_dentry_list+0x274/0x44a
     prune_dcache_sb+0x4a/0x55
     super_cache_scan+0xfc/0x176
     shrink_slab.part.14.constprop.25+0x2a2/0x4d3
     shrink_zone+0x74/0x140
     kswapd+0x6b7/0x930
     kthread+0x107/0x10f
     ret_from_fork+0x3f/0x70
  irq event stamp: 138297
  hardirqs last  enabled at (138297):  debug_check_no_locks_freed+0x113/0x12f
  hardirqs last disabled at (138296):  debug_check_no_locks_freed+0x33/0x12f
  softirqs last  enabled at (137818):  __do_softirq+0x2d3/0x3e9
  softirqs last disabled at (137813):  irq_exit+0x41/0x95

               other info that might help us debug this:
   Possible unsafe locking scenario:
         CPU0
         ----
    lock(jbd2_handle);
    <Interrupt>
      lock(jbd2_handle);

                *** DEADLOCK ***
  5 locks held by git/20158:
   #0:  (sb_writers#7){.+.+.+}, at: [<ffffffff81155411>] mnt_want_write+0x24/0x4b
   lg-devs#1:  (&type->i_mutex_dir_key#2/1){+.+.+.}, at: [<ffffffff81145087>] lock_rename+0xd9/0xe3
   lg-devs#2:  (&sb->s_type->i_mutex_key#11){+.+.+.}, at: [<ffffffff8114f8e2>] lock_two_nondirectories+0x3f/0x6b
   lg-devs#3:  (&sb->s_type->i_mutex_key#11/4){+.+.+.}, at: [<ffffffff8114f909>] lock_two_nondirectories+0x66/0x6b
   lg-devs#4:  (jbd2_handle){+.+.?.}, at: [<ffffffff811e31db>] start_this_handle+0x4ca/0x555

               stack backtrace:
  CPU: 2 PID: 20158 Comm: git Not tainted 4.1.0-rc7-next-20150615-dbg-00016-g8bdf555-dirty #211
  Call Trace:
    dump_stack+0x4c/0x6e
    mark_lock+0x384/0x56d
    mark_held_locks+0x5f/0x76
    lockdep_trace_alloc+0xb2/0xb5
    kmem_cache_alloc_trace+0x32/0x1e2
    zcomp_strm_alloc+0x25/0x73 [zram]
    zcomp_strm_multi_find+0xe7/0x173 [zram]
    zcomp_strm_find+0xc/0xe [zram]
    zram_bvec_rw+0x2ca/0x7e0 [zram]
    zram_make_request+0x1fa/0x301 [zram]
    generic_make_request+0x9c/0xdb
    submit_bio+0xf7/0x120
    ext4_io_submit+0x2e/0x43
    ext4_bio_write_page+0x1b7/0x300
    mpage_submit_page+0x60/0x77
    mpage_map_and_submit_buffers+0x10f/0x21d
    ext4_writepages+0xc8c/0xe1b
    do_writepages+0x23/0x2c
    __filemap_fdatawrite_range+0x84/0x8b
    filemap_flush+0x1c/0x1e
    ext4_alloc_da_blocks+0xb8/0x117
    ext4_rename+0x132/0x6dc
    ? mark_held_locks+0x5f/0x76
    ext4_rename2+0x29/0x2b
    vfs_rename+0x540/0x636
    SyS_renameat2+0x359/0x44d
    SyS_rename+0x1e/0x20
    entry_SYSCALL_64_fastpath+0x12/0x6f

[[email protected]: add stable mark]
Signed-off-by: Sergey Senozhatsky <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Cc: Kyeongdon Kim <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Change-Id: I1ed95ca4937b76634e98b0441c15dd695a43fc62
(cherry picked from commit f19c3ce)
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Dec 22, 2016
(cherry picked from commit 3d5fe03a3ea013060ebba2a811aeb0f23f56aefa)

We can end up allocating a new compression stream with GFP_KERNEL from
within the IO path, which may result is nested (recursive) IO
operations.  That can introduce problems if the IO path in question is a
reclaimer, holding some locks that will deadlock nested IOs.

Allocate streams and working memory using GFP_NOIO flag, forbidding
recursive IO and FS operations.

An example:

  inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
  git/20158 [HC0[0]:SC0[0]:HE1:SE1] takes:
   (jbd2_handle){+.+.?.}, at:  start_this_handle+0x4ca/0x555
  {IN-RECLAIM_FS-W} state was registered at:
     __lock_acquire+0x8da/0x117b
     lock_acquire+0x10c/0x1a7
     start_this_handle+0x52d/0x555
     jbd2__journal_start+0xb4/0x237
     __ext4_journal_start_sb+0x108/0x17e
     ext4_dirty_inode+0x32/0x61
     __mark_inode_dirty+0x16b/0x60c
     iput+0x11e/0x274
     __dentry_kill+0x148/0x1b8
     shrink_dentry_list+0x274/0x44a
     prune_dcache_sb+0x4a/0x55
     super_cache_scan+0xfc/0x176
     shrink_slab.part.14.constprop.25+0x2a2/0x4d3
     shrink_zone+0x74/0x140
     kswapd+0x6b7/0x930
     kthread+0x107/0x10f
     ret_from_fork+0x3f/0x70
  irq event stamp: 138297
  hardirqs last  enabled at (138297):  debug_check_no_locks_freed+0x113/0x12f
  hardirqs last disabled at (138296):  debug_check_no_locks_freed+0x33/0x12f
  softirqs last  enabled at (137818):  __do_softirq+0x2d3/0x3e9
  softirqs last disabled at (137813):  irq_exit+0x41/0x95

               other info that might help us debug this:
   Possible unsafe locking scenario:
         CPU0
         ----
    lock(jbd2_handle);
    <Interrupt>
      lock(jbd2_handle);

                *** DEADLOCK ***
  5 locks held by git/20158:
   #0:  (sb_writers#7){.+.+.+}, at: [<ffffffff81155411>] mnt_want_write+0x24/0x4b
   lg-devs#1:  (&type->i_mutex_dir_key#2/1){+.+.+.}, at: [<ffffffff81145087>] lock_rename+0xd9/0xe3
   lg-devs#2:  (&sb->s_type->i_mutex_key#11){+.+.+.}, at: [<ffffffff8114f8e2>] lock_two_nondirectories+0x3f/0x6b
   lg-devs#3:  (&sb->s_type->i_mutex_key#11/4){+.+.+.}, at: [<ffffffff8114f909>] lock_two_nondirectories+0x66/0x6b
   lg-devs#4:  (jbd2_handle){+.+.?.}, at: [<ffffffff811e31db>] start_this_handle+0x4ca/0x555

               stack backtrace:
  CPU: 2 PID: 20158 Comm: git Not tainted 4.1.0-rc7-next-20150615-dbg-00016-g8bdf555-dirty #211
  Call Trace:
    dump_stack+0x4c/0x6e
    mark_lock+0x384/0x56d
    mark_held_locks+0x5f/0x76
    lockdep_trace_alloc+0xb2/0xb5
    kmem_cache_alloc_trace+0x32/0x1e2
    zcomp_strm_alloc+0x25/0x73 [zram]
    zcomp_strm_multi_find+0xe7/0x173 [zram]
    zcomp_strm_find+0xc/0xe [zram]
    zram_bvec_rw+0x2ca/0x7e0 [zram]
    zram_make_request+0x1fa/0x301 [zram]
    generic_make_request+0x9c/0xdb
    submit_bio+0xf7/0x120
    ext4_io_submit+0x2e/0x43
    ext4_bio_write_page+0x1b7/0x300
    mpage_submit_page+0x60/0x77
    mpage_map_and_submit_buffers+0x10f/0x21d
    ext4_writepages+0xc8c/0xe1b
    do_writepages+0x23/0x2c
    __filemap_fdatawrite_range+0x84/0x8b
    filemap_flush+0x1c/0x1e
    ext4_alloc_da_blocks+0xb8/0x117
    ext4_rename+0x132/0x6dc
    ? mark_held_locks+0x5f/0x76
    ext4_rename2+0x29/0x2b
    vfs_rename+0x540/0x636
    SyS_renameat2+0x359/0x44d
    SyS_rename+0x1e/0x20
    entry_SYSCALL_64_fastpath+0x12/0x6f

[[email protected]: add stable mark]
Signed-off-by: Sergey Senozhatsky <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Cc: Kyeongdon Kim <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Change-Id: I1ed95ca4937b76634e98b0441c15dd695a43fc62
(cherry picked from commit f19c3ce)
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Dec 27, 2016
(cherry picked from commit 3d5fe03a3ea013060ebba2a811aeb0f23f56aefa)

We can end up allocating a new compression stream with GFP_KERNEL from
within the IO path, which may result is nested (recursive) IO
operations.  That can introduce problems if the IO path in question is a
reclaimer, holding some locks that will deadlock nested IOs.

Allocate streams and working memory using GFP_NOIO flag, forbidding
recursive IO and FS operations.

An example:

  inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
  git/20158 [HC0[0]:SC0[0]:HE1:SE1] takes:
   (jbd2_handle){+.+.?.}, at:  start_this_handle+0x4ca/0x555
  {IN-RECLAIM_FS-W} state was registered at:
     __lock_acquire+0x8da/0x117b
     lock_acquire+0x10c/0x1a7
     start_this_handle+0x52d/0x555
     jbd2__journal_start+0xb4/0x237
     __ext4_journal_start_sb+0x108/0x17e
     ext4_dirty_inode+0x32/0x61
     __mark_inode_dirty+0x16b/0x60c
     iput+0x11e/0x274
     __dentry_kill+0x148/0x1b8
     shrink_dentry_list+0x274/0x44a
     prune_dcache_sb+0x4a/0x55
     super_cache_scan+0xfc/0x176
     shrink_slab.part.14.constprop.25+0x2a2/0x4d3
     shrink_zone+0x74/0x140
     kswapd+0x6b7/0x930
     kthread+0x107/0x10f
     ret_from_fork+0x3f/0x70
  irq event stamp: 138297
  hardirqs last  enabled at (138297):  debug_check_no_locks_freed+0x113/0x12f
  hardirqs last disabled at (138296):  debug_check_no_locks_freed+0x33/0x12f
  softirqs last  enabled at (137818):  __do_softirq+0x2d3/0x3e9
  softirqs last disabled at (137813):  irq_exit+0x41/0x95

               other info that might help us debug this:
   Possible unsafe locking scenario:
         CPU0
         ----
    lock(jbd2_handle);
    <Interrupt>
      lock(jbd2_handle);

                *** DEADLOCK ***
  5 locks held by git/20158:
   #0:  (sb_writers#7){.+.+.+}, at: [<ffffffff81155411>] mnt_want_write+0x24/0x4b
   lg-devs#1:  (&type->i_mutex_dir_key#2/1){+.+.+.}, at: [<ffffffff81145087>] lock_rename+0xd9/0xe3
   lg-devs#2:  (&sb->s_type->i_mutex_key#11){+.+.+.}, at: [<ffffffff8114f8e2>] lock_two_nondirectories+0x3f/0x6b
   lg-devs#3:  (&sb->s_type->i_mutex_key#11/4){+.+.+.}, at: [<ffffffff8114f909>] lock_two_nondirectories+0x66/0x6b
   lg-devs#4:  (jbd2_handle){+.+.?.}, at: [<ffffffff811e31db>] start_this_handle+0x4ca/0x555

               stack backtrace:
  CPU: 2 PID: 20158 Comm: git Not tainted 4.1.0-rc7-next-20150615-dbg-00016-g8bdf555-dirty #211
  Call Trace:
    dump_stack+0x4c/0x6e
    mark_lock+0x384/0x56d
    mark_held_locks+0x5f/0x76
    lockdep_trace_alloc+0xb2/0xb5
    kmem_cache_alloc_trace+0x32/0x1e2
    zcomp_strm_alloc+0x25/0x73 [zram]
    zcomp_strm_multi_find+0xe7/0x173 [zram]
    zcomp_strm_find+0xc/0xe [zram]
    zram_bvec_rw+0x2ca/0x7e0 [zram]
    zram_make_request+0x1fa/0x301 [zram]
    generic_make_request+0x9c/0xdb
    submit_bio+0xf7/0x120
    ext4_io_submit+0x2e/0x43
    ext4_bio_write_page+0x1b7/0x300
    mpage_submit_page+0x60/0x77
    mpage_map_and_submit_buffers+0x10f/0x21d
    ext4_writepages+0xc8c/0xe1b
    do_writepages+0x23/0x2c
    __filemap_fdatawrite_range+0x84/0x8b
    filemap_flush+0x1c/0x1e
    ext4_alloc_da_blocks+0xb8/0x117
    ext4_rename+0x132/0x6dc
    ? mark_held_locks+0x5f/0x76
    ext4_rename2+0x29/0x2b
    vfs_rename+0x540/0x636
    SyS_renameat2+0x359/0x44d
    SyS_rename+0x1e/0x20
    entry_SYSCALL_64_fastpath+0x12/0x6f

[[email protected]: add stable mark]
Signed-off-by: Sergey Senozhatsky <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Cc: Kyeongdon Kim <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Change-Id: I1ed95ca4937b76634e98b0441c15dd695a43fc62
(cherry picked from commit f19c3ce)
blastagator pushed a commit to blastagator/LGG2_Kernel that referenced this pull request Jan 26, 2017
commit 058ebd0eba3aff16b144eabf4510ed9510e1416e upstream.

Jiri managed to trigger this warning:

 [] ======================================================
 [] [ INFO: possible circular locking dependency detected ]
 [] 3.10.0+ #228 Tainted: G        W
 [] -------------------------------------------------------
 [] p/6613 is trying to acquire lock:
 []  (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
 []
 [] but task is already holding lock:
 []  (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
 []
 [] which lock already depends on the new lock.
 []
 [] the existing dependency chain (in reverse order) is:
 []
 [] -> lg-devs#4 (&ctx->lock){-.-...}:
 [] -> lg-devs#3 (&rq->lock){-.-.-.}:
 [] -> lg-devs#2 (&p->pi_lock){-.-.-.}:
 [] -> lg-devs#1 (&rnp->nocb_gp_wq[1]){......}:
 [] -> #0 (rcu_node_0){..-...}:

Paul was quick to explain that due to preemptible RCU we cannot call
rcu_read_unlock() while holding scheduler (or nested) locks when part
of the read side critical section was preemptible.

Therefore solve it by making the entire RCU read side non-preemptible.

Also pull out the retry from under the non-preempt to play nice with RT.

Change-Id: Ib93e3be618e05a483b73144994058c886fd780dc
Reported-by: Jiri Olsa <[email protected]>
Helped-out-by: Paul E. McKenney <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Jul 19, 2017
This fixes CVE-2016-8650.

If mpi_powm() is given a zero exponent, it wants to immediately return
either 1 or 0, depending on the modulus.  However, if the result was
initalised with zero limb space, no limbs space is allocated and a
NULL-pointer exception ensues.

Fix this by allocating a minimal amount of limb space for the result when
the 0-exponent case when the result is 1 and not touching the limb space
when the result is 0.

This affects the use of RSA keys and X.509 certificates that carry them.

BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff8138ce5d>] mpi_powm+0x32/0x7e6
PGD 0
Oops: 0002 [lg-devs#1] SMP
Modules linked in:
CPU: 3 PID: 3014 Comm: keyctl Not tainted 4.9.0-rc6-fscache+ #278
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
task: ffff8804011944c0 task.stack: ffff880401294000
RIP: 0010:[<ffffffff8138ce5d>]  [<ffffffff8138ce5d>] mpi_powm+0x32/0x7e6
RSP: 0018:ffff880401297ad8  EFLAGS: 00010212
RAX: 0000000000000000 RBX: ffff88040868bec0 RCX: ffff88040868bba0
RDX: ffff88040868b260 RSI: ffff88040868bec0 RDI: ffff88040868bee0
RBP: ffff880401297ba8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000047 R11: ffffffff8183b210 R12: 0000000000000000
R13: ffff8804087c7600 R14: 000000000000001f R15: ffff880401297c50
FS:  00007f7a7918c700(0000) GS:ffff88041fb80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000401250000 CR4: 00000000001406e0
Stack:
 ffff88040868bec0 0000000000000020 ffff880401297b00 ffffffff81376cd4
 0000000000000100 ffff880401297b10 ffffffff81376d12 ffff880401297b30
 ffffffff81376f37 0000000000000100 0000000000000000 ffff880401297ba8
Call Trace:
 [<ffffffff81376cd4>] ? __sg_page_iter_next+0x43/0x66
 [<ffffffff81376d12>] ? sg_miter_get_next_page+0x1b/0x5d
 [<ffffffff81376f37>] ? sg_miter_next+0x17/0xbd
 [<ffffffff8138ba3a>] ? mpi_read_raw_from_sgl+0xf2/0x146
 [<ffffffff8132a95c>] rsa_verify+0x9d/0xee
 [<ffffffff8132acca>] ? pkcs1pad_sg_set_buf+0x2e/0xbb
 [<ffffffff8132af40>] pkcs1pad_verify+0xc0/0xe1
 [<ffffffff8133cb5e>] public_key_verify_signature+0x1b0/0x228
 [<ffffffff8133d974>] x509_check_for_self_signed+0xa1/0xc4
 [<ffffffff8133cdde>] x509_cert_parse+0x167/0x1a1
 [<ffffffff8133d609>] x509_key_preparse+0x21/0x1a1
 [<ffffffff8133c3d7>] asymmetric_key_preparse+0x34/0x61
 [<ffffffff812fc9f3>] key_create_or_update+0x145/0x399
 [<ffffffff812fe227>] SyS_add_key+0x154/0x19e
 [<ffffffff81001c2b>] do_syscall_64+0x80/0x191
 [<ffffffff816825e4>] entry_SYSCALL64_slow_path+0x25/0x25
Code: 56 41 55 41 54 53 48 81 ec a8 00 00 00 44 8b 71 04 8b 42 04 4c 8b 67 18 45 85 f6 89 45 80 0f 84 b4 06 00 00 85 c0 75 2f 41 ff ce <49> c7 04 24 01 00 00 00 b0 01 75 0b 48 8b 41 18 48 83 38 01 0f
RIP  [<ffffffff8138ce5d>] mpi_powm+0x32/0x7e6
 RSP <ffff880401297ad8>
CR2: 0000000000000000
---[ end trace d82015255d4a5d8d ]---

Basically, this is a backport of a libgcrypt patch:

	http://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=patch;h=6e1adb05d290aeeb1c230c763970695f4a538526

Fixes: cdec9cb ("crypto: GnuPG based MPI lib - source files (part 1)")
Change-Id: Ifeb9f100a650c6308af4a5a9089beeb0c810ec47
Signed-off-by: Andrey Ryabinin <[email protected]>
Signed-off-by: David Howells <[email protected]>
cc: Dmitry Kasatkin <[email protected]>
cc: [email protected]
cc: [email protected]
Signed-off-by: James Morris <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Jul 19, 2017
The class of 4 n_hdls buf locks is the same because a single function
n_hdlc_buf_list_init is used to init all the locks. But since
flush_tx_queue takes n_hdlc->tx_buf_list.spinlock and then calls
n_hdlc_buf_put which takes n_hdlc->tx_free_buf_list.spinlock, lockdep
emits a warning:
=============================================
[ INFO: possible recursive locking detected ]
4.3.0-25.g91e30a7-default lg-devs#1 Not tainted
---------------------------------------------
a.out/1248 is trying to acquire lock:
 (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc]

but task is already holding lock:
 (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&list->spinlock)->rlock);
  lock(&(&list->spinlock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by a.out/1248:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff814c9eb0>] tty_ldisc_ref_wait+0x20/0x50
 lg-devs#1:  (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc]
...
Call Trace:
...
 [<ffffffff81738fd0>] _raw_spin_lock_irqsave+0x50/0x70
 [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc]
 [<ffffffffa01fdc24>] n_hdlc_tty_ioctl+0x144/0x1d0 [n_hdlc]
 [<ffffffff814c25c1>] tty_ioctl+0x3f1/0xe40
...

Fix it by initializing the spin_locks separately. This removes also
reduntand memset of a freshly kzallocated space.

Change-Id: Ied1c2792b8a01d1a0ceff9fb7eea1caa16bac31b
Original-Change-Id: I32bc83c9e19953672857fe8182107772411d471a
Signed-off-by: Jiri Slaby <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Jul 24, 2017
The class of 4 n_hdls buf locks is the same because a single function
n_hdlc_buf_list_init is used to init all the locks. But since
flush_tx_queue takes n_hdlc->tx_buf_list.spinlock and then calls
n_hdlc_buf_put which takes n_hdlc->tx_free_buf_list.spinlock, lockdep
emits a warning:
=============================================
[ INFO: possible recursive locking detected ]
4.3.0-25.g91e30a7-default lg-devs#1 Not tainted
---------------------------------------------
a.out/1248 is trying to acquire lock:
 (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc]

but task is already holding lock:
 (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&list->spinlock)->rlock);
  lock(&(&list->spinlock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by a.out/1248:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff814c9eb0>] tty_ldisc_ref_wait+0x20/0x50
 lg-devs#1:  (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc]
...
Call Trace:
...
 [<ffffffff81738fd0>] _raw_spin_lock_irqsave+0x50/0x70
 [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc]
 [<ffffffffa01fdc24>] n_hdlc_tty_ioctl+0x144/0x1d0 [n_hdlc]
 [<ffffffff814c25c1>] tty_ioctl+0x3f1/0xe40
...

Fix it by initializing the spin_locks separately. This removes also
reduntand memset of a freshly kzallocated space.

Change-Id: Ied1c2792b8a01d1a0ceff9fb7eea1caa16bac31b
Original-Change-Id: I32bc83c9e19953672857fe8182107772411d471a
Signed-off-by: Jiri Slaby <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Jul 27, 2017
The class of 4 n_hdls buf locks is the same because a single function
n_hdlc_buf_list_init is used to init all the locks. But since
flush_tx_queue takes n_hdlc->tx_buf_list.spinlock and then calls
n_hdlc_buf_put which takes n_hdlc->tx_free_buf_list.spinlock, lockdep
emits a warning:
=============================================
[ INFO: possible recursive locking detected ]
4.3.0-25.g91e30a7-default lg-devs#1 Not tainted
---------------------------------------------
a.out/1248 is trying to acquire lock:
 (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc]

but task is already holding lock:
 (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&list->spinlock)->rlock);
  lock(&(&list->spinlock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by a.out/1248:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff814c9eb0>] tty_ldisc_ref_wait+0x20/0x50
 lg-devs#1:  (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc]
...
Call Trace:
...
 [<ffffffff81738fd0>] _raw_spin_lock_irqsave+0x50/0x70
 [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc]
 [<ffffffffa01fdc24>] n_hdlc_tty_ioctl+0x144/0x1d0 [n_hdlc]
 [<ffffffff814c25c1>] tty_ioctl+0x3f1/0xe40
...

Fix it by initializing the spin_locks separately. This removes also
reduntand memset of a freshly kzallocated space.

Change-Id: Ied1c2792b8a01d1a0ceff9fb7eea1caa16bac31b
Original-Change-Id: I32bc83c9e19953672857fe8182107772411d471a
Signed-off-by: Jiri Slaby <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Aug 3, 2017
The class of 4 n_hdls buf locks is the same because a single function
n_hdlc_buf_list_init is used to init all the locks. But since
flush_tx_queue takes n_hdlc->tx_buf_list.spinlock and then calls
n_hdlc_buf_put which takes n_hdlc->tx_free_buf_list.spinlock, lockdep
emits a warning:
=============================================
[ INFO: possible recursive locking detected ]
4.3.0-25.g91e30a7-default lg-devs#1 Not tainted
---------------------------------------------
a.out/1248 is trying to acquire lock:
 (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc]

but task is already holding lock:
 (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&list->spinlock)->rlock);
  lock(&(&list->spinlock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by a.out/1248:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff814c9eb0>] tty_ldisc_ref_wait+0x20/0x50
 lg-devs#1:  (&(&list->spinlock)->rlock){......}, at: [<ffffffffa01fdc07>] n_hdlc_tty_ioctl+0x127/0x1d0 [n_hdlc]
...
Call Trace:
...
 [<ffffffff81738fd0>] _raw_spin_lock_irqsave+0x50/0x70
 [<ffffffffa01fd020>] n_hdlc_buf_put+0x20/0x60 [n_hdlc]
 [<ffffffffa01fdc24>] n_hdlc_tty_ioctl+0x144/0x1d0 [n_hdlc]
 [<ffffffff814c25c1>] tty_ioctl+0x3f1/0xe40
...

Fix it by initializing the spin_locks separately. This removes also
reduntand memset of a freshly kzallocated space.

Change-Id: Ied1c2792b8a01d1a0ceff9fb7eea1caa16bac31b
Original-Change-Id: I32bc83c9e19953672857fe8182107772411d471a
Signed-off-by: Jiri Slaby <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
nasty007 pushed a commit to nasty007/android_kernel_lge_msm8974 that referenced this pull request Aug 18, 2017
commit 058ebd0eba3aff16b144eabf4510ed9510e1416e upstream.

Jiri managed to trigger this warning:

 [] ======================================================
 [] [ INFO: possible circular locking dependency detected ]
 [] 3.10.0+ #228 Tainted: G        W
 [] -------------------------------------------------------
 [] p/6613 is trying to acquire lock:
 []  (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
 []
 [] but task is already holding lock:
 []  (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
 []
 [] which lock already depends on the new lock.
 []
 [] the existing dependency chain (in reverse order) is:
 []
 [] -> lg-devs#4 (&ctx->lock){-.-...}:
 [] -> lg-devs#3 (&rq->lock){-.-.-.}:
 [] -> lg-devs#2 (&p->pi_lock){-.-.-.}:
 [] -> lg-devs#1 (&rnp->nocb_gp_wq[1]){......}:
 [] -> #0 (rcu_node_0){..-...}:

Paul was quick to explain that due to preemptible RCU we cannot call
rcu_read_unlock() while holding scheduler (or nested) locks when part
of the read side critical section was preemptible.

Therefore solve it by making the entire RCU read side non-preemptible.

Also pull out the retry from under the non-preempt to play nice with RT.

Change-Id: I4deef4ac2ed368713baa2d79088e67b894452b40
Original-Change-Id: Ib93e3be618e05a483b73144994058c886fd780dc
Reported-by: Jiri Olsa <[email protected]>
Helped-out-by: Paul E. McKenney <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
hammy007 pushed a commit to hammy007/android_kernel_lge_msm8974 that referenced this pull request Nov 5, 2017
commit 058ebd0eba3aff16b144eabf4510ed9510e1416e upstream.

Jiri managed to trigger this warning:

 [] ======================================================
 [] [ INFO: possible circular locking dependency detected ]
 [] 3.10.0+ #228 Tainted: G        W
 [] -------------------------------------------------------
 [] p/6613 is trying to acquire lock:
 []  (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
 []
 [] but task is already holding lock:
 []  (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
 []
 [] which lock already depends on the new lock.
 []
 [] the existing dependency chain (in reverse order) is:
 []
 [] -> lg-devs#4 (&ctx->lock){-.-...}:
 [] -> lg-devs#3 (&rq->lock){-.-.-.}:
 [] -> lg-devs#2 (&p->pi_lock){-.-.-.}:
 [] -> lg-devs#1 (&rnp->nocb_gp_wq[1]){......}:
 [] -> #0 (rcu_node_0){..-...}:

Paul was quick to explain that due to preemptible RCU we cannot call
rcu_read_unlock() while holding scheduler (or nested) locks when part
of the read side critical section was preemptible.

Therefore solve it by making the entire RCU read side non-preemptible.

Also pull out the retry from under the non-preempt to play nice with RT.

Change-Id: I4deef4ac2ed368713baa2d79088e67b894452b40
Original-Change-Id: Ib93e3be618e05a483b73144994058c886fd780dc
Reported-by: Jiri Olsa <[email protected]>
Helped-out-by: Paul E. McKenney <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
hammy007 pushed a commit to hammy007/android_kernel_lge_msm8974 that referenced this pull request Nov 19, 2017
commit 058ebd0eba3aff16b144eabf4510ed9510e1416e upstream.

Jiri managed to trigger this warning:

 [] ======================================================
 [] [ INFO: possible circular locking dependency detected ]
 [] 3.10.0+ #228 Tainted: G        W
 [] -------------------------------------------------------
 [] p/6613 is trying to acquire lock:
 []  (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
 []
 [] but task is already holding lock:
 []  (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
 []
 [] which lock already depends on the new lock.
 []
 [] the existing dependency chain (in reverse order) is:
 []
 [] -> lg-devs#4 (&ctx->lock){-.-...}:
 [] -> lg-devs#3 (&rq->lock){-.-.-.}:
 [] -> lg-devs#2 (&p->pi_lock){-.-.-.}:
 [] -> lg-devs#1 (&rnp->nocb_gp_wq[1]){......}:
 [] -> #0 (rcu_node_0){..-...}:

Paul was quick to explain that due to preemptible RCU we cannot call
rcu_read_unlock() while holding scheduler (or nested) locks when part
of the read side critical section was preemptible.

Therefore solve it by making the entire RCU read side non-preemptible.

Also pull out the retry from under the non-preempt to play nice with RT.

Change-Id: I4deef4ac2ed368713baa2d79088e67b894452b40
Original-Change-Id: Ib93e3be618e05a483b73144994058c886fd780dc
Reported-by: Jiri Olsa <[email protected]>
Helped-out-by: Paul E. McKenney <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
hammy007 pushed a commit to hammy007/android_kernel_lge_msm8974 that referenced this pull request Nov 20, 2017
commit 058ebd0eba3aff16b144eabf4510ed9510e1416e upstream.

Jiri managed to trigger this warning:

 [] ======================================================
 [] [ INFO: possible circular locking dependency detected ]
 [] 3.10.0+ #228 Tainted: G        W
 [] -------------------------------------------------------
 [] p/6613 is trying to acquire lock:
 []  (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
 []
 [] but task is already holding lock:
 []  (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
 []
 [] which lock already depends on the new lock.
 []
 [] the existing dependency chain (in reverse order) is:
 []
 [] -> lg-devs#4 (&ctx->lock){-.-...}:
 [] -> lg-devs#3 (&rq->lock){-.-.-.}:
 [] -> lg-devs#2 (&p->pi_lock){-.-.-.}:
 [] -> lg-devs#1 (&rnp->nocb_gp_wq[1]){......}:
 [] -> #0 (rcu_node_0){..-...}:

Paul was quick to explain that due to preemptible RCU we cannot call
rcu_read_unlock() while holding scheduler (or nested) locks when part
of the read side critical section was preemptible.

Therefore solve it by making the entire RCU read side non-preemptible.

Also pull out the retry from under the non-preempt to play nice with RT.

Change-Id: I4deef4ac2ed368713baa2d79088e67b894452b40
Original-Change-Id: Ib93e3be618e05a483b73144994058c886fd780dc
Reported-by: Jiri Olsa <[email protected]>
Helped-out-by: Paul E. McKenney <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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