EventQueue overflow

[simonnilsson]

Description

Target
Multiple, tested with stm32l072 target

Tools
Keil uVision

Mbed OS Version
be215a3

As requested by @jeromecoutant I am submitting a new issue for a bug briefly discussed here: #6840.

In equeue_sema_wait in equeue_mbed.cpp if RTOS not present the ms argument is passed as a signed integer and then multiplied by 1000. This causes an overflow in some cases!

Changing this:

timeout.attach_us(callback(equeue_sema_timeout, s), ms*1000);

to this

timeout.attach_us(callback(equeue_sema_timeout, s), (us_timestamp_t)ms*1000);

Solves the problem for me, but it is still handled as a integer outside this function so might be other issues with this.

[ ] Question
[ ] Enhancement
[x] Bug

[ciarmcom]

ARM Internal Ref: MBOTRIAGE-1504

[cmonr]

@simonnilsson Curious. How are you compiling without the RTOS?

[simonnilsson]

@cmonr By adding mbed-os/rtos/* to .mbedignore

[geky]

Oh good catch 👍

I copied your fix into this PR so we can integrate it:
#7782

Let us know if that looks good to you.

I looked at the rest of the code and it looks like that conversion to microseconds was the only issue. The internals of equeue use 32-bit sequence arithmetic, so overflow should be handled gracefully.

Thanks for opening the issue!

[simonnilsson]

@geky Looks good, happy to contribute.