6.6-stable review patch. If anyone has any objections, please let me know.
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From: Duoming Zhou duoming@zju.edu.cn
[ Upstream commit 573601521277119f2e2ba5f28ae6e87fc594f4d4 ]
When the cpu5wdt module is removing, the origin code uses del_timer() to de-activate the timer. If the timer handler is running, del_timer() could not stop it and will return directly. If the port region is released by release_region() and then the timer handler cpu5wdt_trigger() calls outb() to write into the region that is released, the use-after-free bug will happen.
Change del_timer() to timer_shutdown_sync() in order that the timer handler could be finished before the port region is released.
Fixes: e09d9c3e9f85 ("watchdog: cpu5wdt.c: add missing del_timer call") Signed-off-by: Duoming Zhou duoming@zju.edu.cn Reviewed-by: Guenter Roeck linux@roeck-us.net Link: https://lore.kernel.org/r/20240324140444.119584-1-duoming@zju.edu.cn 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 --- drivers/watchdog/cpu5wdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/watchdog/cpu5wdt.c b/drivers/watchdog/cpu5wdt.c index 688b112e712ba..9f279c0e13a66 100644 --- a/drivers/watchdog/cpu5wdt.c +++ b/drivers/watchdog/cpu5wdt.c @@ -252,7 +252,7 @@ static void cpu5wdt_exit(void) if (cpu5wdt_device.queue) { cpu5wdt_device.queue = 0; wait_for_completion(&cpu5wdt_device.stop); - del_timer(&cpu5wdt_device.timer); + timer_shutdown_sync(&cpu5wdt_device.timer); }
misc_deregister(&cpu5wdt_misc);