From: Zou Wei zou_wei@huawei.com
stable inclusion from linux-4.19.198 commit dc9403097be52d57a5c9c35efa9be79d166a78af
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[ Upstream commit c08a6b31e4917034f0ed0cb457c3bb209576f542 ]
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/1620716495-108352-1-git-send-email-zou_wei@huawei.... 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 Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/watchdog/sbc60xxwdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/watchdog/sbc60xxwdt.c b/drivers/watchdog/sbc60xxwdt.c index 87333a41f7538..1702df7f8c386 100644 --- a/drivers/watchdog/sbc60xxwdt.c +++ b/drivers/watchdog/sbc60xxwdt.c @@ -152,7 +152,7 @@ static void wdt_startup(void) static void wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); inb_p(wdt_stop); pr_info("Watchdog timer is now disabled...\n"); }