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authorChengfeng Ye <dg573847474@gmail.com>2023-09-26 10:29:14 +0000
committerBartosz Golaszewski <bartosz.golaszewski@linaro.org>2023-09-27 08:51:28 +0200
commit9e8bc2dda5a7a8e2babc9975f4b11c9a6196e490 (patch)
tree4a4af47269e8c93e5ebb80474928652547d81e50 /drivers
parent6465e260f48790807eef06b583b38ca9789b6072 (diff)
gpio: timberdale: Fix potential deadlock on &tgpio->lock
As timbgpio_irq_enable()/timbgpio_irq_disable() callback could be executed under irq context, it could introduce double locks on &tgpio->lock if it preempts other execution units requiring the same locks. timbgpio_gpio_set() --> timbgpio_update_bit() --> spin_lock(&tgpio->lock) <interrupt> --> timbgpio_irq_disable() --> spin_lock_irqsave(&tgpio->lock) This flaw was found by an experimental static analysis tool I am developing for irq-related deadlock. To prevent the potential deadlock, the patch uses spin_lock_irqsave() on &tgpio->lock inside timbgpio_gpio_set() to prevent the possible deadlock scenario. Signed-off-by: Chengfeng Ye <dg573847474@gmail.com> Reviewed-by: Andy Shevchenko <andy@kernel.org> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/gpio/gpio-timberdale.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/gpio/gpio-timberdale.c b/drivers/gpio/gpio-timberdale.c
index bbd9e9191199..fad979797486 100644
--- a/drivers/gpio/gpio-timberdale.c
+++ b/drivers/gpio/gpio-timberdale.c
@@ -43,9 +43,10 @@ static int timbgpio_update_bit(struct gpio_chip *gpio, unsigned index,
unsigned offset, bool enabled)
{
struct timbgpio *tgpio = gpiochip_get_data(gpio);
+ unsigned long flags;
u32 reg;
- spin_lock(&tgpio->lock);
+ spin_lock_irqsave(&tgpio->lock, flags);
reg = ioread32(tgpio->membase + offset);
if (enabled)
@@ -54,7 +55,7 @@ static int timbgpio_update_bit(struct gpio_chip *gpio, unsigned index,
reg &= ~(1 << index);
iowrite32(reg, tgpio->membase + offset);
- spin_unlock(&tgpio->lock);
+ spin_unlock_irqrestore(&tgpio->lock, flags);
return 0;
}