From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
From: Johan Hovold <johan@xxxxxxxxxx>
commit cf25ef6b631c6fc6c0435fc91eba8734cca20511 upstream.
Make sure to hold the gpio_lock when removing the gpio device from the
gpio_devices list (when dropping the last reference) to avoid corrupting
the list when there are concurrent accesses.
Fixes: ff2b13592299 ("gpio: make the gpiochip a real device")
Cc: stable@xxxxxxxxxxxxxxx # 4.6
Reviewed-by: Saravana Kannan <saravanak@xxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
[ johan: adjust context to 5.11 ]
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpio/gpiolib.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -468,8 +468,12 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid
static void gpiodevice_release(struct device *dev)
{
struct gpio_device *gdev = dev_get_drvdata(dev);
+ unsigned long flags;
+ spin_lock_irqsave(&gpio_lock, flags);
list_del(&gdev->list);
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
ida_free(&gpio_ida, gdev->id);
kfree_const(gdev->label);
kfree(gdev->descs);
