blk-cgroup: hold queue_lock when removing blkg->q_node

When blkg is removed from q->blkg_list from blkg_free_workfn(), queue_lock has to be held, otherwise, all kinds of bugs(list corruption, hard lockup, ..) can be triggered from blkg_destroy_all(). Fixes: f1c006f ("blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()") Cc: Yu Kuai <[email protected]> Cc: xiaoli feng <[email protected]> Cc: Chunyu Hu <[email protected]> Cc: Mike Snitzer <[email protected]> Cc: Tejun Heo <[email protected]> Signed-off-by: Ming Lei <[email protected]> Acked-by: Tejun Heo <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jens Axboe <[email protected]>
kawasaki · Aug 18, 2023 · c164c7b · c164c7b
1 parent 6548fce
commit c164c7b
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
@@ -136,7 +136,9 @@ static void blkg_free_workfn(struct work_struct *work)
 			blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
 	if (blkg->parent)
 		blkg_put(blkg->parent);
+	spin_lock_irq(&q->queue_lock);
 	list_del_init(&blkg->q_node);
+	spin_unlock_irq(&q->queue_lock);
 	mutex_unlock(&q->blkcg_mutex);
 
 	blk_put_queue(q);