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watchdog: sc520_wdt: Fix possible use-after-free in wdt_turnoff()

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[ Upstream commit 90b7c141132244e8e49a34a4c1e445cce33e07f4 ]

This module'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>
Link: https://lore.kernel.org/r/1620716691-108460-1-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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Zou Wei 2021-05-11 15:04:51 +08:00 committed by Greg Kroah-Hartman
parent 146cc288fb
commit 7c56c5508d
1 changed files with 1 additions and 1 deletions
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2
drivers/watchdog/sc520_wdt.c
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@ -186,7 +186,7 @@ static int wdt_startup(void)
static int wdt_turnoff(void) static int wdt_turnoff(void)
{ {
/* Stop the timer */ /* Stop the timer */
del_timer(&timer); del_timer_sync(&timer);
/* Stop the watchdog */ /* Stop the watchdog */
wdt_config(0); wdt_config(0);