On Wed, Nov 01, 2017 at 03:49:57PM -0400, 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). Ideally, this would be
> cleaned up in the 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.
>
> This bug has also been captured at
> https://bugzilla.kernel.org/show_bug.cgi?id=197605
>
> Signed-off-by: Adam Wallis <awallis@xxxxxxxxxxxxxx>
> ---
> drivers/dma/dmatest.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
> index 34ff532..95c662f 100644
> --- a/drivers/dma/dmatest.c
> +++ b/drivers/dma/dmatest.c
> @@ -706,7 +706,7 @@ static int dmatest_func(void *data)
> result("test timed out", total_tests, src_off, dst_off,
> len, 0);
> failed_tests++;
> - continue;
> + BUG();
This will essentially kill the system. People have been trying to remove
usage of BUG(), we should not do that. Complaining violently makes sense..
> } else if (status != DMA_COMPLETE) {
> dmaengine_unmap_put(um);
> result(status == DMA_ERROR ?
> --
> 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.
>
--
~Vinod
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