From 824afb9b04648ea11531fc9047923ec07e7a943d Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 8 May 2025 16:58:05 +0800 Subject: [PATCH] block: move removing elevator after deleting disk->queue_kobj When blk_unregister_queue() is called from add_disk() failure path, there is race in registering/unregistering elevator queue kobject from the two code paths, because commit 559dc11143eb ("block: move elv_register[unregister]_queue out of elevator_lock") moves elevator queue register/unregister out of elevator lock. Fix the race by removing elevator after deleting disk->queue_kobj, because kobject_del(&disk->queue_kobj) drains in-progress sysfs show()/store() of all attributes. Fixes: 559dc11143eb ("block: move elv_register[unregister]_queue out of elevator_lock") Reported-by: Nilay Shroff Suggested-by: Nilay Shroff Signed-off-by: Ming Lei Reviewed-by: Christoph Hellwig Reviewed-by: Nilay Shroff Link: https://lore.kernel.org/r/20250508085807.3175112-3-ming.lei@redhat.com Signed-off-by: Jens Axboe --- block/blk-sysfs.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 8be2390c3c19..b2b9b89d6967 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -948,9 +948,6 @@ void blk_unregister_queue(struct gendisk *disk) blk_mq_sysfs_unregister(disk); blk_crypto_sysfs_unregister(disk); - if (queue_is_mq(q)) - elevator_set_none(q); - mutex_lock(&q->sysfs_lock); disk_unregister_independent_access_ranges(disk); mutex_unlock(&q->sysfs_lock); @@ -959,5 +956,8 @@ void blk_unregister_queue(struct gendisk *disk) kobject_uevent(&disk->queue_kobj, KOBJ_REMOVE); kobject_del(&disk->queue_kobj); + if (queue_is_mq(q)) + elevator_set_none(q); + blk_debugfs_remove(disk); } -- 2.50.1