From: Vincent Whitchurch vincent.whitchurch@axis.com
[ Upstream commit c8fa17d9f08a448184f03d352145099b5beb618e ]
If the irqwork is still scheduled or running while the RTC device is removed, a use-after-free occurs in rtc_timer_do_work(). Cleanup the timerqueue and ensure the work is stopped to fix this.
BUG: KASAN: use-after-free in mutex_lock+0x94/0x110 Write of size 8 at addr ffffff801d846338 by task kworker/3:1/41
Workqueue: events rtc_timer_do_work Call trace: mutex_lock+0x94/0x110 rtc_timer_do_work+0xec/0x630 process_one_work+0x5fc/0x1344 ...
Allocated by task 551: kmem_cache_alloc_trace+0x384/0x6e0 devm_rtc_allocate_device+0xf0/0x574 devm_rtc_device_register+0x2c/0x12c ...
Freed by task 572: kfree+0x114/0x4d0 rtc_device_release+0x64/0x80 device_release+0x8c/0x1f4 kobject_put+0x1c4/0x4b0 put_device+0x20/0x30 devm_rtc_release_device+0x1c/0x30 devm_action_release+0x54/0x90 release_nodes+0x124/0x310 devres_release_group+0x170/0x240 i2c_device_remove+0xd8/0x314 ...
Last potentially related work creation: insert_work+0x5c/0x330 queue_work_on+0xcc/0x154 rtc_set_time+0x188/0x5bc rtc_dev_ioctl+0x2ac/0xbd0 ...
Signed-off-by: Vincent Whitchurch vincent.whitchurch@axis.com Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Link: https://lore.kernel.org/r/20211210160951.7718-1-vincent.whitchurch@axis.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/rtc/class.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 4b460c61f1d8..40d504dac1a9 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -26,6 +26,15 @@ struct class *rtc_class; static void rtc_device_release(struct device *dev) { struct rtc_device *rtc = to_rtc_device(dev); + struct timerqueue_head *head = &rtc->timerqueue; + struct timerqueue_node *node; + + mutex_lock(&rtc->ops_lock); + while ((node = timerqueue_getnext(head))) + timerqueue_del(head, node); + mutex_unlock(&rtc->ops_lock); + + cancel_work_sync(&rtc->irqwork);
ida_simple_remove(&rtc_ida, rtc->id); mutex_destroy(&rtc->ops_lock);