From b7b4d3426d2b5ecab21578eb20d8e456a1aace8f Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Wed, 27 Apr 2011 14:24:19 +0100 Subject: mmc: sdhci: Check mrq->cmd in sdhci_tasklet_finish 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 Signed-off-by: Mark Brown Cc: Signed-off-by: Chris Ball --- drivers/mmc/host/sdhci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/mmc/host/sdhci.c') diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 9e15f41f87be..fd8f488df5fa 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1345,7 +1345,7 @@ 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))) { -- cgit v1.2.2 From 0c9c99a765321104cc5f9c97f949382a9ba4927e Mon Sep 17 00:00:00 2001 From: Chris Ball Date: Wed, 27 Apr 2011 17:35:31 -0400 Subject: mmc: sdhci: Check mrq != NULL in sdhci_tasklet_finish It seems that under certain circumstances the sdhci_tasklet_finish() call can be entered with mrq set to NULL, causing the system to crash with a NULL pointer de-reference. Seen on S3C6410 system. Based on a patch by Dimitris Papastamos. Reported-by: Dimitris Papastamos Cc: Signed-off-by: Chris Ball --- drivers/mmc/host/sdhci.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/mmc/host/sdhci.c') diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index fd8f488df5fa..5d20661bc357 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1334,6 +1334,13 @@ static void sdhci_tasklet_finish(unsigned long param) host = (struct sdhci_host*)param; + /* + * If this tasklet gets rescheduled while running, it will + * be run again afterwards but without any active request. + */ + if (!host->mrq) + return; + spin_lock_irqsave(&host->lock, flags); del_timer(&host->timer); -- cgit v1.2.2