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Subject[PATCH 059/241] mmc: sdhci: fix NULL dereference in sdhci_request() tuning
Date
3.5.7.2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chris Ball <cjb@laptop.org>

commit 14efd957209461bbdf285bf0d67e931955d04a4c upstream.

Commit 473b095a72a9 ("mmc: sdhci: fix incorrect command used in tuning")
introduced a NULL dereference at resume-time if an SD 3.0 host controller
raises the SDHCI_NEEDS_TUNING flag while no card is inserted. Seen on an
OLPC XO-4 with sdhci-pxav3, but presumably affects other controllers too.

Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
drivers/mmc/host/sdhci.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 1dffebe..732ab1a 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1294,16 +1294,19 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
*/
if ((host->flags & SDHCI_NEEDS_RETUNING) &&
!(present_state & (SDHCI_DOING_WRITE | SDHCI_DOING_READ))) {
- /* eMMC uses cmd21 while sd and sdio use cmd19 */
- tuning_opcode = mmc->card->type == MMC_TYPE_MMC ?
- MMC_SEND_TUNING_BLOCK_HS200 :
- MMC_SEND_TUNING_BLOCK;
- spin_unlock_irqrestore(&host->lock, flags);
- sdhci_execute_tuning(mmc, tuning_opcode);
- spin_lock_irqsave(&host->lock, flags);
-
- /* Restore original mmc_request structure */
- host->mrq = mrq;
+ if (mmc->card) {
+ /* eMMC uses cmd21 but sd and sdio use cmd19 */
+ tuning_opcode =
+ mmc->card->type == MMC_TYPE_MMC ?
+ MMC_SEND_TUNING_BLOCK_HS200 :
+ MMC_SEND_TUNING_BLOCK;
+ spin_unlock_irqrestore(&host->lock, flags);
+ sdhci_execute_tuning(mmc, tuning_opcode);
+ spin_lock_irqsave(&host->lock, flags);
+
+ /* Restore original mmc_request structure */
+ host->mrq = mrq;
+ }
}

if (mrq->sbc && !(host->flags & SDHCI_AUTO_CMD23))
--
1.7.9.5


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