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 <dp@opensource.wolfsonmicro.com>
Cc: <stable@kernel.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index fd8f488..5d20661 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1334,6 +1334,13 @@
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);