[PATCH 08/91] mmc: sdhci: Check mrq->cmd in sdhci_tasklet_finish

From: Willy Tarreau
Date: Sun Feb 05 2012 - 17:48:08 EST


2.6.27-longterm review patch. If anyone has any objections, please let us know.

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

commit b7b4d3426d2b5ecab21578eb20d8e456a1aace8f upstream.

It seems that under certain circumstances that the sdhci_tasklet_finish()
call can be entered with mrq->cmd set to NULL, causing the system to crash
with a NULL pointer de-reference.

Unable to handle kernel NULL pointer dereference at virtual address 00000000
PC is at sdhci_tasklet_finish+0x34/0xe8
LR is at sdhci_tasklet_finish+0x24/0xe8

Seen on S3C6410 system.

Signed-off-by: Ben Dooks <ben-linux@xxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Chris Ball <cjb@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/mmc/host/sdhci.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

Index: longterm-2.6.27/drivers/mmc/host/sdhci.c
===================================================================
--- longterm-2.6.27.orig/drivers/mmc/host/sdhci.c 2012-02-05 22:34:34.798915250 +0100
+++ longterm-2.6.27/drivers/mmc/host/sdhci.c 2012-02-05 22:34:36.053916156 +0100
@@ -1176,7 +1176,7 @@
* upon error conditions.
*/
if (!(host->flags & SDHCI_DEVICE_DEAD) &&
- (mrq->cmd->error ||
+ ((mrq->cmd && mrq->cmd->error) ||
(mrq->data && (mrq->data->error ||
(mrq->data->stop && mrq->data->stop->error))) ||
(host->quirks & SDHCI_QUIRK_RESET_AFTER_REQUEST))) {


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