[PATCH 1/2] MMC: SDHCI: Check mrq->cmd in sdhci_tasklet_finish

[Dimitris Papastamos <dp@opensource.wolfsonmicro.com>]

From: Ben Dooks <ben-linux@fluff.org>

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@fluff.org>
---
 drivers/mmc/host/sdhci.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 79ebc39..e75d070 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1341,7 +1341,7 @@ static void sdhci_tasklet_finish(unsigned long param)
 	 * 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))) {
-- 
1.7.4.2