Commit 63c21180 authored Nov 05, 2013 by Chuansheng Liu Committed by Chris Ball Jan 13, 2014

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>

parent 00411135

drivers/mmc/host/sdhci.c

+7 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1396,6 +1396,13 @@ static void sdhci_request(struct mmc_host mmc, struct mmc_request mrq)
	mmc->card->type == MMC_TYPE_MMC ?		mmc->card->type == MMC_TYPE_MMC ?
	MMC_SEND_TUNING_BLOCK_HS200 :		MMC_SEND_TUNING_BLOCK_HS200 :
	MMC_SEND_TUNING_BLOCK;		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);		spin_unlock_irqrestore(&host->lock, flags);
	sdhci_execute_tuning(mmc, tuning_opcode);		sdhci_execute_tuning(mmc, tuning_opcode);
	spin_lock_irqsave(&host->lock, flags);		spin_lock_irqsave(&host->lock, flags);