Re: [PATCH 3.16 083/254] dmaengine: dmatest: move callback wait queue to thread context

Adam Wallis
2018-02-28T17:47:50Z

Ben

On 2/28/2018 10:20 AM, Ben Hutchings wrote:
> 3.16.55-rc1 review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Adam Wallis <awallis@codeaurora.org>
>
> commit 6f6a23a213be51728502b88741ba6a10cda2441d upstream.
>
> 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.
>
> 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@codeaurora.org>
> Suggested-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
> Signed-off-by: Adam Wallis <awallis@codeaurora.org>
> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
[..]

Make sure you pick up the following bug fix on whatever branch you apply the
above patch to

>From 66b3bd2356e0a1531c71a3dcf96944621e25c17c Mon Sep 17 00:00:00 2001
From: Yang Shunyong <shunyong.yang@hxt-semitech.com>
Date: Mon, 29 Jan 2018 14:40:11 +0800
Subject: dmaengine: dmatest: fix container_of member in dmatest_callback

From: Yang Shunyong <shunyong.yang@hxt-semitech.com>

commit 66b3bd2356e0a1531c71a3dcf96944621e25c17c upstream.

The type of arg passed to dmatest_callback is struct dmatest_done.
It refers to test_done in struct dmatest_thread, not done_wait.

Fixes: 6f6a23a213be ("dmaengine: dmatest: move callback wait ...")
Signed-off-by: Yang Shunyong <shunyong.yang@hxt-semitech.com>
Acked-by: Adam Wallis <awallis@codeaurora.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

--
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.