[PATCH 3.12 043/182] mfd: tps65910: Fix possible invalid pointer dereference on regmap_add_irq_chip fail

Jiri Slaby
2014-05-13T10:06:45Z

From: Krzysztof Kozlowski <k.kozlowski@samsung.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

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@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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 d79277204835..de87eafbeb05 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;
}

--
1.9.3