gpio: gpio-grgpio: fix possible sleep-in-atomic-context bugs in grgpio_irq_map/unmap()
authorJia-Ju Bai <baijiaju1990@gmail.com>
Wed, 18 Dec 2019 13:26:05 +0000 (21:26 +0800)
committerLinus Walleij <linus.walleij@linaro.org>
Tue, 7 Jan 2020 12:37:11 +0000 (13:37 +0100)
commite36eaf94be8f7bc4e686246eed3cf92d845e2ef8
tree35e276dbcb0a9666d6e339cbd75e68d4b4f9794d
parent25d071b3f6dbe4c4b9c9d0df76fbe9292310e799
gpio: gpio-grgpio: fix possible sleep-in-atomic-context bugs in grgpio_irq_map/unmap()

The driver may sleep while holding a spinlock.
The function call path (from bottom to top) in Linux 4.19 is:

drivers/gpio/gpio-grgpio.c, 261:
request_irq in grgpio_irq_map
drivers/gpio/gpio-grgpio.c, 255:
_raw_spin_lock_irqsave in grgpio_irq_map

drivers/gpio/gpio-grgpio.c, 318:
free_irq in grgpio_irq_unmap
drivers/gpio/gpio-grgpio.c, 299:
_raw_spin_lock_irqsave in grgpio_irq_unmap

request_irq() and free_irq() can sleep at runtime.

To fix these bugs, request_irq() and free_irq() are called without
holding the spinlock.

These bugs are found by a static analysis tool STCheck written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Link: https://lore.kernel.org/r/20191218132605.10594-1-baijiaju1990@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
drivers/gpio/gpio-grgpio.c