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gpiolib: of: don't mark hog nodes OF_POPULATED before a chip is found

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When a gpio-hog node is attached by a device-tree overlay before its
parent GPIO chip has been registered, of_gpio_notify() sets
OF_POPULATED on the node via of_node_test_and_set_flag() and only then
discovers that there is no gpio_device for the parent, returning
NOTIFY_DONE without clearing the flag.

Since gpiochip_hog_lines() skips any hog child whose of_node carries
OF_POPULATED, the leaked flag makes the hog silently ignored when the
chip is registered later. Applying an overlay containing both a GPIO
controller node and its hog children - and populating devices only
after the overlay apply completes - hits this on every boot; the hog
is only applied if the chip driver is unbound (which clears the flag
in the remove path) and rebound.

Look up the parent gpio_device before claiming the node so that a hog
attached ahead of its chip stays unclaimed and is picked up normally
by gpiochip_hog_lines() at registration time.

Signed-off-by: Abdurrahman Hussain <abdurrahman@nexthop.ai>
Fixes: a23226b7c1 ("gpiolib: handle gpio-hogs only once")
Cc: stable@vger.kernel.org
Reviewed-by: Daniel Drake <dan@reactivated.net>
Link: https://patch.msgid.link/20260815-gpiolib-of-hog-flag-leak-v1-1-6126aac5f6f3@nexthop.ai
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
This commit is contained in:
Abdurrahman Hussain 2026-08-15 13:44:19 -07:00 committed by Bartosz Golaszewski
parent 49bda48268
commit 1f1d0812f6
1 changed files with 3 additions and 3 deletions
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6
drivers/gpio/gpiolib-of.c
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@ -788,13 +788,13 @@ static int of_gpio_notify(struct notifier_block *nb, unsigned long action,
if (!of_property_read_bool(rd->dn, "gpio-hog"))
return NOTIFY_DONE; /* not for us */
if (of_node_test_and_set_flag(rd->dn, OF_POPULATED))
return NOTIFY_DONE;
gdev = of_find_gpio_device_by_node(rd->dn->parent);
if (!gdev)
return NOTIFY_DONE; /* not for us */
if (of_node_test_and_set_flag(rd->dn, OF_POPULATED))
return NOTIFY_DONE;
ret = gpiochip_add_hog(gpio_device_get_chip(gdev), of_fwnode_handle(rd->dn));
if (ret < 0) {
pr_err("%s: failed to add hogs for %pOF\n", __func__,