6.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Zheng Qixing zhengqixing@huawei.com
[ Upstream commit 343dc5423bfe876c12bb80c56f5e44286e442a07 ]
Device-mapper can call add_disk() multiple times for the same gendisk due to its two-phase creation process (dm create + dm load). This leads to kobject double initialization errors when the underlying iSCSI devices become temporarily unavailable and then reappear.
However, if the first add_disk() call fails and is retried, the queue_kobj gets initialized twice, causing:
kobject: kobject (ffff88810c27bb90): tried to init an initialized object, something is seriously wrong. Call Trace: <TASK> dump_stack_lvl+0x5b/0x80 kobject_init.cold+0x43/0x51 blk_register_queue+0x46/0x280 add_disk_fwnode+0xb5/0x280 dm_setup_md_queue+0x194/0x1c0 table_load+0x297/0x2d0 ctl_ioctl+0x2a2/0x480 dm_ctl_ioctl+0xe/0x20 __x64_sys_ioctl+0xc7/0x110 do_syscall_64+0x72/0x390 entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fix this by separating kobject initialization from sysfs registration: - Initialize queue_kobj early during gendisk allocation - add_disk() only adds the already-initialized kobject to sysfs - del_gendisk() removes from sysfs but doesn't destroy the kobject - Final cleanup happens when the disk is released
Fixes: 2bd85221a625 ("block: untangle request_queue refcounting from sysfs") Reported-by: Li Lingfeng lilingfeng3@huawei.com Closes: https://lore.kernel.org/all/83591d0b-2467-433c-bce0-5581298eb161@huawei.com/ Signed-off-by: Zheng Qixing zhengqixing@huawei.com Reviewed-by: Ming Lei ming.lei@redhat.com Reviewed-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Nilay Shroff nilay@linux.ibm.com Link: https://lore.kernel.org/r/20250808053609.3237836-1-zhengqixing@huaweicloud.c... Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-sysfs.c | 12 +++++------- block/blk.h | 1 + block/genhd.c | 2 ++ 3 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index c611444480b3..de39746de18b 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -821,7 +821,7 @@ static void blk_queue_release(struct kobject *kobj) /* nothing to do here, all data is associated with the parent gendisk */ }
-static const struct kobj_type blk_queue_ktype = { +const struct kobj_type blk_queue_ktype = { .default_groups = blk_queue_attr_groups, .sysfs_ops = &queue_sysfs_ops, .release = blk_queue_release, @@ -849,15 +849,14 @@ int blk_register_queue(struct gendisk *disk) struct request_queue *q = disk->queue; int ret;
- kobject_init(&disk->queue_kobj, &blk_queue_ktype); ret = kobject_add(&disk->queue_kobj, &disk_to_dev(disk)->kobj, "queue"); if (ret < 0) - goto out_put_queue_kobj; + return ret;
if (queue_is_mq(q)) { ret = blk_mq_sysfs_register(disk); if (ret) - goto out_put_queue_kobj; + goto out_del_queue_kobj; } mutex_lock(&q->sysfs_lock);
@@ -908,8 +907,8 @@ int blk_register_queue(struct gendisk *disk) mutex_unlock(&q->sysfs_lock); if (queue_is_mq(q)) blk_mq_sysfs_unregister(disk); -out_put_queue_kobj: - kobject_put(&disk->queue_kobj); +out_del_queue_kobj: + kobject_del(&disk->queue_kobj); return ret; }
@@ -960,5 +959,4 @@ void blk_unregister_queue(struct gendisk *disk) elevator_set_none(q);
blk_debugfs_remove(disk); - kobject_put(&disk->queue_kobj); } diff --git a/block/blk.h b/block/blk.h index fae7653a941f..4746a7704856 100644 --- a/block/blk.h +++ b/block/blk.h @@ -19,6 +19,7 @@ struct elevator_type; /* Max future timer expiry for timeouts */ #define BLK_MAX_TIMEOUT (5 * HZ)
+extern const struct kobj_type blk_queue_ktype; extern struct dentry *blk_debugfs_root;
struct blk_flush_queue { diff --git a/block/genhd.c b/block/genhd.c index c26733f6324b..9bbc38d12792 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1303,6 +1303,7 @@ static void disk_release(struct device *dev) disk_free_zone_resources(disk); xa_destroy(&disk->part_tbl);
+ kobject_put(&disk->queue_kobj); disk->queue->disk = NULL; blk_put_queue(disk->queue);
@@ -1486,6 +1487,7 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id, INIT_LIST_HEAD(&disk->slave_bdevs); #endif mutex_init(&disk->rqos_state_mutex); + kobject_init(&disk->queue_kobj, &blk_queue_ktype); return disk;
out_erase_part0: