This is a note to let you know that I've just added the patch titled
dmaengine: dmatest: warn user when dma test times out
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dmaengine-dmatest-warn-user-when-dma-test-times-out.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a9df21e34b422f79d9a9fa5c3eff8c2a53491be6 Mon Sep 17 00:00:00 2001
From: Adam Wallis <awallis@xxxxxxxxxxxxxx>
Date: Thu, 2 Nov 2017 08:53:30 -0400
Subject: dmaengine: dmatest: warn user when dma test times out
From: Adam Wallis <awallis@xxxxxxxxxxxxxx>
commit a9df21e34b422f79d9a9fa5c3eff8c2a53491be6 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). Ideally, this would be
cleaned up in the thread handler, but at the very least, the kernel
is left in a very precarious scenario that can lead to some long debug
sessions when the crash comes later.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=197605
Signed-off-by: Adam Wallis <awallis@xxxxxxxxxxxxxx>
Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma/dmatest.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -634,6 +634,7 @@ static int dmatest_func(void *data)
* free it this time?" dancing. For now, just
* leave it dangling.
*/
+ WARN(1, "dmatest: Kernel stack may be corrupted!!\n");
dmaengine_unmap_put(um);
result("test timed out", total_tests, src_off, dst_off,
len, 0);
Patches currently in stable-queue which might be from awallis@xxxxxxxxxxxxxx are
queue-4.4/dmaengine-dmatest-warn-user-when-dma-test-times-out.patch