4.4-stable review patch. If anyone has any objections, please let me know.
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From: Adam Wallis awallis@codeaurora.org
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@codeaurora.org Signed-off-by: Vinod Koul vinod.koul@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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);