[PATCH] drivers: gpio: gpio-adp5588: Fix sleep-in-atomic-context bug

[PATCH] drivers: gpio: gpio-adp5588: Fix sleep-in-atomic-context bug

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

This fixes:
[BUG] gpio: gpio-adp5588: A possible sleep-in-atomic-context bug
                          in adp5588_gpio_write()
[BUG] gpio: gpio-adp5588: A possible sleep-in-atomic-context bug
                          in adp5588_gpio_direction_input()

Reported-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
---
 drivers/gpio/gpio-adp5588.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-adp5588.c b/drivers/gpio/gpio-adp5588.c
index e717f8d..202d367 100644
--- a/drivers/gpio/gpio-adp5588.c
+++ b/drivers/gpio/gpio-adp5588.c
@@ -41,6 +41,8 @@ struct adp5588_gpio {
 	uint8_t int_en[3];
 	uint8_t irq_mask[3];
 	uint8_t irq_stat[3];
+	uint8_t int_input_en[3];
+	uint8_t int_lvl_cached[3];
 };
 
 static int adp5588_gpio_read(struct i2c_client *client, u8 reg)
@@ -173,12 +175,28 @@ static void adp5588_irq_bus_sync_unlock(struct irq_data *d)
 	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
 	int i;
 
-	for (i = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++)
+	for (i = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++) {
+		if (dev->int_input_en[i]) {
+			mutex_lock(&dev->lock);
+			dev->dir[i] &= ~dev->int_input_en[i];
+			dev->int_input_en[i] = 0;
+			adp5588_gpio_write(dev->client, GPIO_DIR1 + i,
+					   dev->dir[i]);
+			mutex_unlock(&dev->lock);
+		}
+
+		if (dev->int_lvl_cached[i] != dev->int_lvl[i]) {
+			dev->int_lvl_cached[i] = dev->int_lvl[i];
+			adp5588_gpio_write(dev->client, GPIO_INT_LVL1 + i,
+					   dev->int_lvl[i]);
+		}
+
 		if (dev->int_en[i] ^ dev->irq_mask[i]) {
 			dev->int_en[i] = dev->irq_mask[i];
 			adp5588_gpio_write(dev->client, GPIO_INT_EN1 + i,
 					   dev->int_en[i]);
 		}
+	}
 
 	mutex_unlock(&dev->irq_lock);
 }
@@ -221,9 +239,7 @@ static int adp5588_irq_set_type(struct irq_data *d, unsigned int type)
 	else
 		return -EINVAL;
 
-	adp5588_gpio_direction_input(&dev->gpio_chip, gpio);
-	adp5588_gpio_write(dev->client, GPIO_INT_LVL1 + bank,
-			   dev->int_lvl[bank]);
+	dev->int_input_en[bank] |= bit;
 
 	return 0;
 }
-- 
2.7.4

Re: [PATCH] drivers: gpio: gpio-adp5588: Fix sleep-in-atomic-context bug

[Linus Walleij]

On Mon, Aug 13, 2018 at 3:53 PM <michael.hennerich@analog.com> wrote:

> From: Michael Hennerich <michael.hennerich@analog.com>
>
> This fixes:
> [BUG] gpio: gpio-adp5588: A possible sleep-in-atomic-context bug
>                           in adp5588_gpio_write()
> [BUG] gpio: gpio-adp5588: A possible sleep-in-atomic-context bug
>                           in adp5588_gpio_direction_input()
>
> Reported-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>

Thanks Michael, excellent and prompt fix. Patch applied
for fixes (v4.19-rcs).

Should we even tag it for stable?

Yours,
Linus Walleij

Re: [PATCH] drivers: gpio: gpio-adp5588: Fix sleep-in-atomic-context bug

[Michael Hennerich]

On 29.08.2018 10:55, Linus Walleij wrote:
> On Mon, Aug 13, 2018 at 3:53 PM <michael.hennerich@analog.com> wrote:
> 
>> From: Michael Hennerich <michael.hennerich@analog.com>
>>
>> This fixes:
>> [BUG] gpio: gpio-adp5588: A possible sleep-in-atomic-context bug
>>                            in adp5588_gpio_write()
>> [BUG] gpio: gpio-adp5588: A possible sleep-in-atomic-context bug
>>                            in adp5588_gpio_direction_input()
>>
>> Reported-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
> 
> Thanks Michael, excellent and prompt fix. Patch applied
> for fixes (v4.19-rcs).
> 
> Should we even tag it for stable?

Thanks, Linus - Yes that would make sense.

-- 
Greetings,
Michael

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