| From | Paul Gortmaker <> | Subject | [34-longterm 109/196] mmc: sdhci: Check mrq != NULL in sdhci_tasklet_finish | Date | Mon, 12 Mar 2012 20:20:22 -0400 |
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From: Chris Ball <cjb@laptop.org>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
commit 0c9c99a765321104cc5f9c97f949382a9ba4927e upstream.
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> Signed-off-by: Chris Ball <cjb@laptop.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- drivers/mmc/host/sdhci.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 6441e22..be410d7 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1268,6 +1268,13 @@ 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); -- 1.7.9.3
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