Commit c08a6b31 authored by Zou Wei's avatar Zou Wei Committed by Wim Van Sebroeck

watchdog: Fix possible use-after-free in wdt_startup()

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: default avatarHulk Robot <hulkci@huawei.com>
Signed-off-by: default avatarZou Wei <zou_wei@huawei.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1620716495-108352-1-git-send-email-zou_wei@huawei.comSigned-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@linux-watchdog.org>
parent e0b101ab
......@@ -146,7 +146,7 @@ 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");
}
......
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