[PATCH 1/2] mfd: tps65910: Fix possible invalid pointer dereference on regmap_add_irq_chip fail

[PATCH 1/2] mfd: tps65910: Fix possible invalid pointer dereference on regmap_add_irq_chip fail

[Krzysztof Kozlowski]

tps65910_irq_init() sets the 'tps65910->chip_irq' before calling
regmap_add_irq_chip(). If this 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 null.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: <stable@vger.kernel.org>
Fixes: 4aab3fadad32 ("mfd: tps65910: Move interrupt implementation code to mfd file")
---
 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 1f142d76cbbc..d6573318977f 100644
--- a/drivers/mfd/tps65910.c
+++ b/drivers/mfd/tps65910.c
@@ -251,16 +251,18 @@ static int tps65910_irq_init(struct tps65910 *tps65910, int irq,
 		break;
 	}
 
 	tps65910->chip_irq = 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;
 }
 
 static int tps65910_irq_exit(struct tps65910 *tps65910)
 {
 	if (tps65910->chip_irq > 0)
 		regmap_del_irq_chip(tps65910->chip_irq, tps65910->irq_data);
-- 
1.7.9.5

Re: [PATCH 1/2] mfd: tps65910: Fix possible invalid pointer dereference on regmap_add_irq_chip fail

[Lee Jones]

> tps65910_irq_init() sets the 'tps65910->chip_irq' before calling
> regmap_add_irq_chip(). If this 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 null.
> 
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Cc: <stable@vger.kernel.org>
> Fixes: 4aab3fadad32 ("mfd: tps65910: Move interrupt implementation code to mfd file")
> ---
>  drivers/mfd/tps65910.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Applied after cleaning up the commit message a little.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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