kernel/linux.git/drivers/gpio/gpiolib-cdev.c, branch v6.18.21

gpio: cdev: Fix resource leaks on errors in gpiolib_cdev_register()

2026-01-30T09:32:27+00:00

commit 8a8c942cad4cd12f739a8bb60cac77fd173c4e07 upstream. On error handling paths, gpiolib_cdev_register() doesn't free the allocated resources which results leaks. Fix it. Cc: stable@vger.kernel.org Fixes: 7b9b77a8bba9 ("gpiolib: add a per-gpio_device line state notification workqueue") Fixes: d83cee3d2bb1 ("gpio: protect the pointer to gpio_chip in gpio_device with SRCU") Signed-off-by: Tzung-Bi Shih Link: https://lore.kernel.org/r/20260120092650.2305319-1-tzungbi@kernel.org Signed-off-by: Bartosz Golaszewski Signed-off-by: Greg Kroah-Hartman

gpio: cdev: Fix resource leaks on errors in lineinfo_changed_notify()

2026-01-30T09:32:27+00:00

commit 70b3c280533167749a8f740acaa8ef720f78f984 upstream. On error handling paths, lineinfo_changed_notify() doesn't free the allocated resources which results leaks. Fix it. Cc: stable@vger.kernel.org Fixes: d4cd0902c156 ("gpio: cdev: make sure the cdev fd is still active before emitting events") Signed-off-by: Tzung-Bi Shih Link: https://lore.kernel.org/r/20260120030857.2144847-1-tzungbi@kernel.org Signed-off-by: Bartosz Golaszewski Signed-off-by: Greg Kroah-Hartman

gpio: cdev: Correct return code on memory allocation failure

2026-01-30T09:32:27+00:00

commit faff6846474e99295a139997f93ef6db222b5cee upstream. -ENOMEM is a more appropriate return code for memory allocation failures. Correct it. Cc: stable@vger.kernel.org Fixes: 20bddcb40b2b ("gpiolib: cdev: replace locking wrappers for gpio_device with guards") Signed-off-by: Tzung-Bi Shih Link: https://lore.kernel.org/r/20260116081036.352286-6-tzungbi@kernel.org Signed-off-by: Bartosz Golaszewski Signed-off-by: Greg Kroah-Hartman

gpiolib: rename GPIO chip printk macros

2026-01-17T15:35:21+00:00

[ Upstream commit d4f335b410ddbe3e99f48f8b5ea78a25041274f1 ] The chip_$level() macros take struct gpio_chip as argument so make it follow the convention of using the 'gpiochip_' prefix. Reviewed-by: Linus Walleij Signed-off-by: Bartosz Golaszewski Stable-dep-of: a7ac22d53d09 ("gpiolib: fix race condition for gdev->srcu") Signed-off-by: Sasha Levin

gpio: cdev: make sure the cdev fd is still active before emitting events

2025-11-19T11:00:28+00:00

With the final call to fput() on a file descriptor, the release action may be deferred and scheduled on a work queue. The reference count of that descriptor is still zero and it must not be used. It's possible that a GPIO change, we want to notify the user-space about, happens AFTER the reference count on the file descriptor associated with the character device went down to zero but BEFORE the .release() callback was called from the workqueue and so BEFORE we unregistered from the notifier. Using the regular get_file() routine in this situation triggers the following warning: struct file::f_count incremented from zero; use-after-free condition present! So use the get_file_active() variant that will return NULL on file descriptors that have been or are being released. Fixes: 40b7c49950bd ("gpio: cdev: put emitting the line state events on a workqueue") Reported-by: Alexander Sverdlin Closes: https://lore.kernel.org/all/5d605f7fc99456804911403102a4fe999a14cc85.camel@siemens.com/ Tested-by: Alexander Sverdlin Link: https://lore.kernel.org/r/20251117-gpio-cdev-get-file-v1-1-28a16b5985b8@linaro.org Signed-off-by: Bartosz Golaszewski

gpiolib: add a common prefix to GPIO descriptor flags

2025-09-12T07:20:38+00:00

While these flags are private within drivers/gpio/, when looking at the code, it's not really clear they are GPIO-specific. Since these are GPIO descriptor flags, prepend their names with a common "GPIOD" prefix. While at it: update the flags' docs: make spelling consistent, correct outdated information, etc. Reviewed-by: Linus Walleij Link: https://lore.kernel.org/r/20250909-rename-gpio-flags-v1-1-bda208a40856@linaro.org Signed-off-by: Bartosz Golaszewski

gpiolib: don't allow setting values on input lines

2025-04-07T07:00:48+00:00

Some drivers as well as the character device and sysfs code check whether the line actually is in output mode before allowing the user to set a value. However, GPIO value setters now return integer values and can indicate failures. This allows us to move these checks into the core code. Reviewed-by: Linus Walleij Link: https://lore.kernel.org/r/20250311-gpio-set-check-output-v1-1-d971bca9e6fa@linaro.org Signed-off-by: Bartosz Golaszewski

gpio: cdev: use raw notifier for line state events

2025-03-13T08:20:12+00:00

We use a notifier to implement the mechanism of informing the user-space about changes in GPIO line status. We register with the notifier when the GPIO character device file is opened and unregister when the last reference to the associated file descriptor is dropped. Since commit fcc8b637c542 ("gpiolib: switch the line state notifier to atomic") we use the atomic notifier variant. Atomic notifiers call rcu_synchronize in atomic_notifier_chain_unregister() which caused a significant performance regression in some circumstances, observed by user-space when calling close() on the GPIO device file descriptor. Replace the atomic notifier with the raw variant and provide synchronization with a read-write spinlock. Fixes: fcc8b637c542 ("gpiolib: switch the line state notifier to atomic") Reported-by: David Jander Closes: https://lore.kernel.org/all/20250311110034.53959031@erd003.prtnl/ Tested-by: David Jander Tested-by: Kent Gibson Link: https://lore.kernel.org/r/20250311-gpiolib-line-state-raw-notifier-v2-1-138374581e1e@linaro.org Signed-off-by: Bartosz Golaszewski

gpiolib: cdev: use !mem_is_zero() instead of memchr_inv(s, 0, n)

2024-11-12T08:46:17+00:00

Use the mem_is_zero() helper where possible. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20241110201706.16614-1-andy.shevchenko@gmail.com Signed-off-by: Bartosz Golaszewski

gpio: cdev: don't report GPIOs requested as interrupts as used

2024-11-04T08:08:11+00:00

GPIOs used as shared irqs can still be requested by user-space (or kernel drivers for that matter) yet we report them as used over the chardev ABI. Drop the test for FLAG_USED_AS_IRQ from gpio_desc_to_lineinfo(). Reviewed-by: Kent Gibson Reviewed-by: Linus Walleij Link: https://lore.kernel.org/r/20241031200842.22712-1-brgl@bgdev.pl Signed-off-by: Bartosz Golaszewski