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 <[email protected]> Cc: <[email protected]> Signed-off-by: Chris Ball <[email protected]>
mgowda · Apr 27, 2011 · 0c9c99a · 0c9c99a
1 parent b7b4d34
commit 0c9c99a
Showing 1 changed file with 7 additions and 0 deletions.
diff --git 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);