blk-throttle: fix UAF by deleteing timer in blk_throtl_exit()

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 <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jens Axboe <[email protected]>
ambv · Sep 7, 2021 · 884f0e8 · 884f0e8
1 parent dfbb340
commit 884f0e8
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
@@ -2458,6 +2458,7 @@ 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]);