From 0a10d107818cc4def73723ba3101aae0d25ea353 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Tue, 12 Dec 2023 11:55:01 +0100 Subject: gpiolib: allocate memory atomically with a spinlock held We will eventually switch to protecting the GPIO descriptors with a mutex but until then, we need to allocate memory for the label copy atomically while we're holding the global spinlock. Reported-by: Dan Carpenter Closes: https://lore.kernel.org/linux-gpio/62588146-eed6-42f7-ba26-160226b109fe@moroto.mountain/T/#u Fixes: f8d05e276b45 ("gpiolib: remove gpiochip_is_requested()") Signed-off-by: Bartosz Golaszewski Reviewed-by: Linus Walleij --- drivers/gpio/gpiolib.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'drivers/gpio') diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 4e190be75dc2..6efe44570333 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2399,7 +2399,15 @@ char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset) if (!test_bit(FLAG_REQUESTED, &desc->flags)) return NULL; - label = kstrdup(desc->label, GFP_KERNEL); + /* + * FIXME: Once we mark gpiod_direction_input/output() and + * gpiod_get_direction() with might_sleep(), we'll be able to protect + * the GPIO descriptors with mutex (while value setting operations will + * become lockless). + * + * Until this happens, this allocation needs to be atomic. + */ + label = kstrdup(desc->label, GFP_ATOMIC); if (!label) return ERR_PTR(-ENOMEM); -- cgit v1.2.3