buffer: avoid aliasing MmapMut references #1025
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`Buffer` has an `UnsafeCell<MmapMut>`. It protects against concurrent writes to it by using a mutex. However, it has UB by allowing callers of `read()` and `write()` to concurrently have mutable and immutable references to the `MmapMut`. This patch avoids the alias by using a pointer instead. Thanks to @Ralith for spotting the problem and suggesting the fix during our review of unsafe Rust code at Google.
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@martinvonz has updated the pull request. You must reimport the pull request before landing. |
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This pull request has been merged in c373376. |
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Bufferhas anUnsafeCell<MmapMut>. It protects against concurrent writes to it by using a mutex. However, it has UB by allowing callers ofread()andwrite()to concurrently have mutable and immutable references to theMmapMut. This patch avoids the alias by using a pointer instead.Thanks to @Ralith for spotting the problem and suggesting the fix during our review of unsafe Rust code at Google.