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watchdog: Fix possible use-after-free by calling del_timer_sync()
authorZou Wei <zou_wei@huawei.com>
Wed, 12 May 2021 06:57:56 +0000 (14:57 +0800)
committerWim Van Sebroeck <wim@linux-watchdog.org>
Mon, 21 Jun 2021 06:49:03 +0000 (08:49 +0200)
commitd0212f095ab56672f6f36aabc605bda205e1e0bf
treeb8e7ed858241af9a664bf25a72751ce7f7bbaf4e
parent90b7c141132244e8e49a34a4c1e445cce33e07f4
watchdog: Fix possible use-after-free by calling del_timer_sync()

This driver's remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver's remove function
has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Link: https://lore.kernel.org/r/1620802676-19701-1-git-send-email-zou_wei@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
drivers/watchdog/lpc18xx_wdt.c
drivers/watchdog/w83877f_wdt.c