linux-kernel - [PATCH 4.13 44/44] dmaengine: dmatest: warn user when dma test times out

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20171116172825.521259003@linuxfoundation.org>
Date:   Thu, 16 Nov 2017 18:43:08 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Adam Wallis <awallis@...eaurora.org>,
        Vinod Koul <vinod.koul@...el.com>
Subject: [PATCH 4.13 44/44] dmaengine: dmatest: warn user when dma test times out

4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Adam Wallis <awallis@...eaurora.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@...eaurora.org>
Signed-off-by: Vinod Koul <vinod.koul@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/dma/dmatest.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -696,6 +696,7 @@ 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);