[PATCH v5] dmaengine: dmatest: move callback wait queue to thread context

[Adam Wallis]

On 11/27/2017 10:45 AM, Adam Wallis wrote:
> Commit adfa543e7314 ("dmatest: don't use set_freezable_with_signal()")
> introduced a bug (that is in fact documented by the patch commit text)
> that leaves behind a dangling pointer. Since the done_wait structure is
> allocated on the stack, future invocations to the DMATEST can produce
> undesirable results (e.g., corrupted spinlocks).
> 
> Commit a9df21e34b42 ("dmaengine: dmatest: warn user when dma test times
> out") attempted to WARN the user that the stack was likely corrupted but
> did not fix the actual issue.
> 
> This patch fixes the issue by pushing the wait queue and callback
> structs into the the thread structure. If a failure occurs due to time,
> dmaengine_terminate_all will force the callback to safely call
> wake_up_all() without possibility of using a freed pointer.
> 
> Cc: stable at vger.kernel.org
> Bug: https://bugzilla.kernel.org/show_bug.cgi?id=197605
> Fixes: adfa543e7314 ("dmatest: don't use set_freezable_with_signal()")
> Reviewed-by: Sinan Kaya <okaya at codeaurora.org>
> Suggested-by: Shunyong Yang <shunyong.yang at hxt-semitech.com>
> Signed-off-by: Adam Wallis <awallis at codeaurora.org>
> ---
> changes from v4: Change "done" to "arg" in container_of for x86 compiler
> changes from v3: Added check to thread wait variable if terminate_all fails
> changes from v2: Added "Fixes" tag
> changes from v1: Added pre-req patches for stable
[..]

Vinod, did you have any feedback on this patch or any changes that should be
made? I was still hoping this bugfix would make it into the 4.15 kernel.

Thanks!

Adam


-- 
Adam Wallis
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.