mmc: sdhci: Setting the host->mrq to NULL before executing tuning
In function sdhci_request(), it is possible to do the tuning execution
like below:
sdhci_request() {
spin_lock_irqsave(&host->lock, flags);
host->mrq = mrq;
...
spin_unlock_irqrestore(&host->lock, flags);
<=== Here it is possible one pending finish_tasklet get running
and it will operate the original mrq, and notified the mrq
is done, and causes memory corruption.
sdhci_execute_tuning(mmc, tuning_opcode);
spin_lock_irqsave(&host->lock, flags);
host->mrq = mrq;
...
}
In the above race place, the original mrq should not be finished wrongly,
so here before unlock the spinlock, we need to set the host->mrq to NULL
to avoid this case.
Signed-off-by: Liu, Chuansheng <chuansheng.liu@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 6840322..cc00bed 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1396,6 +1396,13 @@
mmc->card->type == MMC_TYPE_MMC ?
MMC_SEND_TUNING_BLOCK_HS200 :
MMC_SEND_TUNING_BLOCK;
+
+ /* Here we need to set the host->mrq to NULL,
+ * in case the pending finish_tasklet
+ * finishes it incorrectly.
+ */
+ host->mrq = NULL;
+
spin_unlock_irqrestore(&host->lock, flags);
sdhci_execute_tuning(mmc, tuning_opcode);
spin_lock_irqsave(&host->lock, flags);
