From: Zheng Qixing Date: Fri, 8 Aug 2025 05:36:09 +0000 (+0800) Subject: block: fix kobject double initialization in add_disk X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=343dc5423bfe876c12bb80c56f5e44286e442a07;p=users%2Fhch%2Fmisc.git block: fix kobject double initialization in add_disk 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: 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 Closes: https://lore.kernel.org/all/83591d0b-2467-433c-bce0-5581298eb161@huawei.com/ Signed-off-by: Zheng Qixing Reviewed-by: Ming Lei Reviewed-by: Yu Kuai Reviewed-by: Nilay Shroff Link: https://lore.kernel.org/r/20250808053609.3237836-1-zhengqixing@huaweicloud.com Signed-off-by: Jens Axboe --- diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 396cded255ea..c5cf79a20842 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -847,7 +847,7 @@ 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, @@ -875,15 +875,14 @@ 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); @@ -934,8 +933,8 @@ out_debugfs_remove: 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; } @@ -986,5 +985,4 @@ 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 0a2eccf28ca4..46f566f9b126 100644 --- a/block/blk.h +++ b/block/blk.h @@ -29,6 +29,7 @@ struct elevator_tags; /* 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: