From: Li Jinlin lijinlin3@huawei.com

mainline inclusion from mainline-5.14 commit 884f0e84f1e3195b801319c8ec3d5774e9bf2710 category: bugfix bugzilla: NA CVE: NA

The pending timer has been set up in blk_throtl_init(). However, the timer is not deleted in blk_throtl_exit(). This means that the timer handler may still be running after freeing the timer, which would result in a use-after-free.

Fix by calling del_timer_sync() to delete the timer in blk_throtl_exit().

Signed-off-by: Li Jinlin lijinlin3@huawei.com Link: https://lore.kernel.org/r/20210907121242.2885564-1-lijinlin3@huawei.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Laibin Qiu qiulaibin@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- block/blk-throttle.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 9426330d99dda..2c6df348faf5f 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2482,6 +2482,7 @@ int blk_throtl_init(struct request_queue *q) void blk_throtl_exit(struct request_queue *q) { BUG_ON(!q->td); + del_timer_sync(&q->td->service_queue.pending_timer); throtl_shutdown_wq(q); blkcg_deactivate_policy(q, &blkcg_policy_throtl); free_percpu(q->td->latency_buckets[READ]);