[ 3.5.y.z extended stable ] Patch "mmc: sdhci: fix NULL dereference in sdhci_request() tuning" has been added to staging queue

[Herton Ronaldo Krzesinski]

This is a note to let you know that I have just added a patch titled

    mmc: sdhci: fix NULL dereference in sdhci_request() tuning

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From cd3502f40a7d326fbe725d5abca83e42560986be Mon Sep 17 00:00:00 2001
From: Chris Ball <cjb at laptop.org>
Date: Mon, 5 Nov 2012 14:29:49 -0500
Subject: [PATCH] mmc: sdhci: fix NULL dereference in sdhci_request() tuning
X-Extended-Stable: 3.5

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 at laptop.org>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at 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