[PATCH 2/2] gpio: shared: fix a race condition

[Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>]

When matching the reset-gpio reference with the actual firmware node
consuming the GPIO, we also need to lock the structure associated with
the latter as it can change while we're doing it.

Fixes: 49416483a953 ("gpio: shared: allow sharing a reset-gpios pin between reset-gpio and gpiolib")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/all/00107523-7737-4b92-a785-14ce4e93b8cb@samsung.com/
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
 drivers/gpio/gpiolib-shared.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpio/gpiolib-shared.c b/drivers/gpio/gpiolib-shared.c
index a68af06a6cc4e1e33946d7f200cecd4d3dc066af..198951c4c80bc0965c4b45a97f4f41ecc1f517b3 100644
--- a/drivers/gpio/gpiolib-shared.c
+++ b/drivers/gpio/gpiolib-shared.c
@@ -378,6 +378,8 @@ static bool gpio_shared_dev_is_reset_gpio(struct device *consumer,
 	 * arguments match the ones from this consumer's node.
 	 */
 	list_for_each_entry(real_ref, &entry->refs, list) {
+		guard(mutex)(&real_ref->lock);
+
 		if (!real_ref->fwnode)
 			continue;
 

-- 
2.47.3