[3.8.y.z extended stable] Patch "mfd: tps65910: Fix possible invalid pointer dereference on regmap_add_irq_chip fail" has been added to staging queue

[Kamal Mostafa]

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

    mfd: tps65910: Fix possible invalid pointer dereference on regmap_add_irq_chip fail

to the linux-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.22.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 2faabcff065f46e68af84ae75718d52338d974ef Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <k.kozlowski at samsung.com>
Date: Wed, 12 Mar 2014 16:50:44 +0100
Subject: mfd: tps65910: Fix possible invalid pointer dereference on
 regmap_add_irq_chip fail

commit 483e2dfdbc94751430e41db9973985f5b054d322 upstream.

Fixes: 4aab3fadad32 ("mfd: tps65910: Move interrupt implementation code to mfd file")

tps65910_irq_init() sets 'tps65910->chip_irq' before calling
regmap_add_irq_chip(). If the regmap_add_irq_chip() call fails in
memory allocation of regmap_irq_chip_data members then:

1. The 'tps65910->chip_irq' will still hold some value
2. 'tps65910->irq_data' will be pointing to already freed memory
   (because regmap_add_irq_chip() will free it on error)

This results in invalid memory access during driver remove because the
tps65910_irq_exit() tests whether 'tps65910->chip_irq' is not zero.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski at samsung.com>
Signed-off-by: Lee Jones <lee.jones at linaro.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/mfd/tps65910.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/tps65910.c b/drivers/mfd/tps65910.c
index d792772..de87eaf 100644
--- a/drivers/mfd/tps65910.c
+++ b/drivers/mfd/tps65910.c
@@ -254,8 +254,10 @@ static int tps65910_irq_init(struct tps65910 *tps65910, int irq,
 	ret = regmap_add_irq_chip(tps65910->regmap, tps65910->chip_irq,
 		IRQF_ONESHOT, pdata->irq_base,
 		tps6591x_irqs_chip, &tps65910->irq_data);
-	if (ret < 0)
+	if (ret < 0) {
 		dev_warn(tps65910->dev, "Failed to add irq_chip %d\n", ret);
+		tps65910->chip_irq = 0;
+	}
 	return ret;
 }

--
1.9.1