| Message ID | 1430752248-15401-11-git-send-email-johan@kernel.org |
|---|---|
| State | New |
| Headers | show |
On Mon, May 4, 2015 at 5:10 PM, Johan Hovold <johan@kernel.org> wrote: > Make sure to release any irq only after the class device has been > deregistered. > > This avoids a race between gpiod_unexport and edge_store, where an irq > could be allocated just before the gpio class device is deregistered > without relying on FLAG_EXPORT and the global sysfs lock. > > Note that there is no need to hold the sysfs lock when releasing the irq > after the class device is gone as kernfs will prevent further attribute > operations. > > Signed-off-by: Johan Hovold <johan@kernel.org> Patch applied. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index a78dabd4035b..e4b079eec9bc 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -695,7 +695,6 @@ void gpiod_unexport(struct gpio_desc *desc) dev = class_find_device(&gpio_class, NULL, desc, match_export); if (dev) { - gpio_setup_irq(desc, dev, 0); clear_bit(FLAG_SYSFS_DIR, &desc->flags); clear_bit(FLAG_EXPORT, &desc->flags); } else @@ -706,6 +705,11 @@ void gpiod_unexport(struct gpio_desc *desc) if (dev) { device_unregister(dev); + /* + * Release irq after deregistration to prevent race with + * edge_store. + */ + gpio_setup_irq(desc, dev, 0); put_device(dev); }
Make sure to release any irq only after the class device has been deregistered. This avoids a race between gpiod_unexport and edge_store, where an irq could be allocated just before the gpio class device is deregistered without relying on FLAG_EXPORT and the global sysfs lock. Note that there is no need to hold the sysfs lock when releasing the irq after the class device is gone as kernfs will prevent further attribute operations. Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/gpio/gpiolib-sysfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)