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possible deadlock in kernfs_link_sibling (2)

Status: upstream: reported on 2026/03/17 17:33
Subsystems: kernfs
[Documentation on labels]
Reported-by: syzbot+dd764a450d93885d847f@syzkaller.appspotmail.com
First crash: 57d, last: 17m
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[syzbot] Monthly kernfs report (Apr 2026) 0 (1) 2026/04/29 20:32
Re: [syzbot] possible deadlock in kernfs_link_sibling (2) 1 (1) 2026/03/18 15:23
[syzbot] [kernfs?] possible deadlock in kernfs_link_sibling (2) 0 (1) 2026/03/17 17:33
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in kernfs_link_sibling kernfs 4 30 215d 246d 0/29 closed as invalid on 2025/10/25 16:44

Sample crash report:
Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
kworker/u9:1/12412 is trying to acquire lock:
ffff88801c6a5210 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: kernfs_link_sibling+0x555/0x850 fs/kernfs/dir.c:411

but task is already holding lock:
ffff88801c6a5180 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x38/0x850 fs/kernfs/dir.c:826

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #10 (&root->kernfs_rwsem){++++}-{4:4}:
       down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1625
       kernfs_add_one+0x38/0x850 fs/kernfs/dir.c:826
       kernfs_create_dir_ns+0xfc/0x1a0 fs/kernfs/dir.c:1131
       internal_create_group+0x36f/0xf40 fs/sysfs/group.c:176
       cpuhp_invoke_callback+0x3ab/0x9a0 kernel/cpu.c:194
       cpuhp_issue_call+0x1b8/0x970 kernel/cpu.c:2354
       __cpuhp_setup_state_cpuslocked+0x431/0x880 kernel/cpu.c:2507
       __cpuhp_setup_state+0xf4/0x300 kernel/cpu.c:2536
       do_one_initcall+0x121/0x750 init/main.c:1392
       do_initcall_level init/main.c:1454 [inline]
       do_initcalls init/main.c:1470 [inline]
       do_basic_setup init/main.c:1490 [inline]
       kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703
       kernel_init+0x1f/0x1e0 init/main.c:1593
       ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #9 (cpuhp_state_mutex){+.+.}-{4:4}:

-> #8 (cpu_hotplug_lock){++++}-{0:0}:
       percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
       percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
       cpus_read_lock+0x42/0x170 kernel/cpu.c:490
       static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190
       fl_create+0x7fb/0xd10 net/ipv6/ip6_flowlabel.c:452
       ipv6_flowlabel_get net/ipv6/ip6_flowlabel.c:632 [inline]
       ipv6_flowlabel_opt+0x519/0x2d40 net/ipv6/ip6_flowlabel.c:735
       do_ipv6_setsockopt+0x1b80/0x44b0 net/ipv6/ipv6_sockglue.c:928
       ipv6_setsockopt+0xcb/0x170 net/ipv6/ipv6_sockglue.c:965
       sctp_setsockopt+0x161/0xb370 net/sctp/socket.c:4586
       do_sock_setsockopt+0xf3/0x1d0 net/socket.c:2381
       __sys_setsockopt+0x195/0x220 net/socket.c:2406
       __do_sys_setsockopt net/socket.c:2412 [inline]
       __se_sys_setsockopt net/socket.c:2409 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2409
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #7 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x41/0xf0 net/core/sock.c:3783
       lock_sock include/net/sock.h:1713 [inline]
       inet_shutdown+0x67/0x410 net/ipv4/af_inet.c:915
       nbd_mark_nsock_dead+0xae/0x5c0 drivers/block/nbd.c:318
       sock_shutdown+0x16b/0x200 drivers/block/nbd.c:411
       nbd_clear_sock drivers/block/nbd.c:1427 [inline]
       nbd_config_put+0x1eb/0x750 drivers/block/nbd.c:1451
       nbd_genl_connect+0xaf8/0x1a40 drivers/block/nbd.c:2248
       genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
       genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
       genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
       netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
       genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
       netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
       netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
       netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
       sock_sendmsg_nosec net/socket.c:787 [inline]
       __sock_sendmsg net/socket.c:802 [inline]
       ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
       ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
       __sys_sendmsg+0x170/0x220 net/socket.c:2784
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:820
       nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
       nbd_queue_rq+0x428/0x1080 drivers/block/nbd.c:1207
       blk_mq_dispatch_rq_list+0x422/0x1e70 block/blk-mq.c:2148
       __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
       blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
       __blk_mq_sched_dispatch_requests+0xcea/0x1620 block/blk-mq-sched.c:307
       blk_mq_sched_dispatch_requests+0xd7/0x1c0 block/blk-mq-sched.c:329
       blk_mq_run_hw_queue+0x23c/0x670 block/blk-mq.c:2386
       blk_mq_dispatch_list+0x51d/0x1360 block/blk-mq.c:2949
       blk_mq_flush_plug_list block/blk-mq.c:2997 [inline]
       blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2969
       __blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1230
       blk_finish_plug block/blk-core.c:1257 [inline]
       __submit_bio+0x584/0x6c0 block/blk-core.c:649
       __submit_bio_noacct_mq block/blk-core.c:722 [inline]
       submit_bio_noacct_nocheck+0x543/0xbf0 block/blk-core.c:753
       submit_bio_noacct+0xd18/0x2000 block/blk-core.c:884
       blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline]
       submit_bh_wbc+0x681/0x890 fs/buffer.c:2737
       submit_bh fs/buffer.c:2742 [inline]
       block_read_full_folio+0x264/0x8e0 fs/buffer.c:2344
       filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2502
       do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4107
       read_mapping_folio include/linux/pagemap.h:1017 [inline]
       read_part_sector+0xd1/0x370 block/partitions/core.c:724
       adfspart_check_ICS+0x91/0x7d0 block/partitions/acorn.c:356
       check_partition block/partitions/core.c:143 [inline]
       blk_add_partitions block/partitions/core.c:591 [inline]
       bdev_disk_changed+0x7a3/0x1250 block/partitions/core.c:695
       blkdev_get_whole+0x187/0x290 block/bdev.c:756
       bdev_open+0x2c7/0xe40 block/bdev.c:965
       blkdev_open+0x34e/0x4f0 block/fops.c:697
       do_dentry_open+0x6d8/0x1660 fs/open.c:947
       vfs_open+0x82/0x3f0 fs/open.c:1079
       do_open fs/namei.c:4699 [inline]
       path_openat+0x208c/0x31a0 fs/namei.c:4858
       do_file_open+0x20e/0x430 fs/namei.c:4887
       do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
       do_sys_open fs/open.c:1370 [inline]
       __do_sys_openat fs/open.c:1386 [inline]
       __se_sys_openat fs/open.c:1381 [inline]
       __x64_sys_openat+0x12d/0x210 fs/open.c:1381
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:820
       nbd_queue_rq+0xba/0x1080 drivers/block/nbd.c:1199
       blk_mq_dispatch_rq_list+0x422/0x1e70 block/blk-mq.c:2148
       __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
       blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
       __blk_mq_sched_dispatch_requests+0xcea/0x1620 block/blk-mq-sched.c:307
       blk_mq_sched_dispatch_requests+0xd7/0x1c0 block/blk-mq-sched.c:329
       blk_mq_run_hw_queue+0x23c/0x670 block/blk-mq.c:2386
       blk_mq_dispatch_list+0x51d/0x1360 block/blk-mq.c:2949
       blk_mq_flush_plug_list block/blk-mq.c:2997 [inline]
       blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2969
       __blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1230
       blk_finish_plug block/blk-core.c:1257 [inline]
       __submit_bio+0x584/0x6c0 block/blk-core.c:649
       __submit_bio_noacct_mq block/blk-core.c:722 [inline]
       submit_bio_noacct_nocheck+0x543/0xbf0 block/blk-core.c:753
       submit_bio_noacct+0xd18/0x2000 block/blk-core.c:884
       blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline]
       submit_bh_wbc+0x681/0x890 fs/buffer.c:2737
       submit_bh fs/buffer.c:2742 [inline]
       block_read_full_folio+0x264/0x8e0 fs/buffer.c:2344
       filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2502
       do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4107
       read_mapping_folio include/linux/pagemap.h:1017 [inline]
       read_part_sector+0xd1/0x370 block/partitions/core.c:724
       adfspart_check_ICS+0x91/0x7d0 block/partitions/acorn.c:356
       check_partition block/partitions/core.c:143 [inline]
       blk_add_partitions block/partitions/core.c:591 [inline]
       bdev_disk_changed+0x7a3/0x1250 block/partitions/core.c:695
       blkdev_get_whole+0x187/0x290 block/bdev.c:756
       bdev_open+0x2c7/0xe40 block/bdev.c:965
       blkdev_open+0x34e/0x4f0 block/fops.c:697
       do_dentry_open+0x6d8/0x1660 fs/open.c:947
       vfs_open+0x82/0x3f0 fs/open.c:1079
       do_open fs/namei.c:4699 [inline]
       path_openat+0x208c/0x31a0 fs/namei.c:4858
       do_file_open+0x20e/0x430 fs/namei.c:4887
       do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
       do_sys_open fs/open.c:1370 [inline]
       __do_sys_openat fs/open.c:1386 [inline]
       __se_sys_openat fs/open.c:1381 [inline]
       __x64_sys_openat+0x12d/0x210 fs/open.c:1381
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (set->srcu){.+.+}-{0:0}:
       srcu_lock_sync include/linux/srcu.h:199 [inline]
       __synchronize_srcu+0xa2/0x300 kernel/rcu/srcutree.c:1481
       blk_mq_wait_quiesce_done block/blk-mq.c:284 [inline]
       blk_mq_wait_quiesce_done block/blk-mq.c:281 [inline]
       blk_mq_quiesce_queue block/blk-mq.c:304 [inline]
       blk_mq_quiesce_queue+0x149/0x1c0 block/blk-mq.c:299
       elevator_switch+0x17b/0x7e0 block/elevator.c:576
       elevator_change+0x352/0x530 block/elevator.c:681
       elevator_set_default+0x29e/0x360 block/elevator.c:754
       blk_register_queue+0x48e/0x630 block/blk-sysfs.c:987
       __add_disk+0x73f/0xe40 block/genhd.c:528
       add_disk_fwnode+0x118/0x5c0 block/genhd.c:597
       add_disk include/linux/blkdev.h:794 [inline]
       nbd_dev_add+0x77a/0xb10 drivers/block/nbd.c:1984
       nbd_init+0x291/0x2b0 drivers/block/nbd.c:2692
       do_one_initcall+0x121/0x750 init/main.c:1392
       do_initcall_level init/main.c:1454 [inline]
       do_initcalls init/main.c:1470 [inline]
       do_basic_setup init/main.c:1490 [inline]
       kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703
       kernel_init+0x1f/0x1e0 init/main.c:1593
       ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #3 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:820
       elevator_change+0x1bc/0x530 block/elevator.c:679
       elevator_set_none+0x92/0xf0 block/elevator.c:769
       blk_mq_elv_switch_none block/blk-mq.c:5131 [inline]
       __blk_mq_update_nr_hw_queues block/blk-mq.c:5176 [inline]
       blk_mq_update_nr_hw_queues+0x4c1/0x15f0 block/blk-mq.c:5241
       nbd_start_device+0x1a6/0xbd0 drivers/block/nbd.c:1489
       nbd_genl_connect+0xff2/0x1a40 drivers/block/nbd.c:2239
       genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
       genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
       genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
       netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
       genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
       netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
       netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
       netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
       sock_sendmsg_nosec net/socket.c:787 [inline]
       __sock_sendmsg net/socket.c:802 [inline]
       ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
       ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
       __sys_sendmsg+0x170/0x220 net/socket.c:2784
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&q->q_usage_counter(io)#54){++++}-{0:0}:
       blk_alloc_queue+0x610/0x790 block/blk-core.c:461
       blk_mq_alloc_queue+0x174/0x290 block/blk-mq.c:4450
       __blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4497
       nbd_dev_add+0x492/0xb10 drivers/block/nbd.c:1954
       nbd_init+0x291/0x2b0 drivers/block/nbd.c:2692
       do_one_initcall+0x121/0x750 init/main.c:1392
       do_initcall_level init/main.c:1454 [inline]
       do_initcalls init/main.c:1470 [inline]
       do_basic_setup init/main.c:1490 [inline]
       kernel_init_freeable+0x6ea/0x7b0 init/main.c:1703
       kernel_init+0x1f/0x1e0 init/main.c:1593
       ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #1 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:4325 [inline]
       fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4339
       might_alloc include/linux/sched/mm.h:317 [inline]
       slab_pre_alloc_hook mm/slub.c:4520 [inline]
       slab_alloc_node mm/slub.c:4875 [inline]
       kmem_cache_alloc_noprof+0x4c/0x6e0 mm/slub.c:4905
       __kernfs_iattrs+0x124/0x3e0 fs/kernfs/inode.c:36
       kernfs_iattrs fs/kernfs/inode.c:59 [inline]
       __kernfs_setattr+0x4d/0x3c0 fs/kernfs/inode.c:72
       kernfs_iop_setattr+0xda/0x130 fs/kernfs/inode.c:126
       notify_change+0xb25/0x1330 fs/attr.c:556
       do_truncate+0x1df/0x240 fs/open.c:68
       handle_truncate fs/namei.c:4307 [inline]
       do_open fs/namei.c:4703 [inline]
       path_openat+0x2a55/0x31a0 fs/namei.c:4858
       do_file_open+0x20e/0x430 fs/namei.c:4887
       do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
       do_sys_open fs/open.c:1370 [inline]
       __do_sys_openat fs/open.c:1386 [inline]
       __se_sys_openat fs/open.c:1381 [inline]
       __x64_sys_openat+0x12d/0x210 fs/open.c:1381
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&root->kernfs_iattr_rwsem){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
       down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1625
       kernfs_link_sibling+0x555/0x850 fs/kernfs/dir.c:411
       kernfs_add_one+0x1e7/0x850 fs/kernfs/dir.c:845
       kernfs_create_dir_ns+0xfc/0x1a0 fs/kernfs/dir.c:1131
       sysfs_create_dir_ns+0x13a/0x2b0 fs/sysfs/dir.c:59
       create_dir lib/kobject.c:73 [inline]
       kobject_add_internal+0x2c8/0x930 lib/kobject.c:240
       kobject_add_varg lib/kobject.c:374 [inline]
       kobject_add+0x16a/0x1e0 lib/kobject.c:426
       device_add+0x294/0x1950 drivers/base/core.c:3629
       hci_conn_add_sysfs+0x1a3/0x260 net/bluetooth/hci_sysfs.c:48
       hci_conn_complete_evt+0x5bb/0x13f0 net/bluetooth/hci_event.c:3200
       hci_event_func net/bluetooth/hci_event.c:7796 [inline]
       hci_event_packet+0x8e9/0xcd0 net/bluetooth/hci_event.c:7847
       hci_rx_work+0x451/0xfc0 net/bluetooth/hci_core.c:4077
       process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302
       process_scheduled_works kernel/workqueue.c:3385 [inline]
       worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466
       kthread+0x370/0x450 kernel/kthread.c:436
       ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  &root->kernfs_iattr_rwsem --> cpuhp_state_mutex --> &root->kernfs_rwsem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&root->kernfs_rwsem);
                               lock(cpuhp_state_mutex);
                               lock(&root->kernfs_rwsem);
  lock(&root->kernfs_iattr_rwsem);

 *** DEADLOCK ***

4 locks held by kworker/u9:1/12412:
 #0: ffff8880793da940 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277
 #1: ffffc900036bfd08 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278
 #2: ffff8880682ac0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_conn_complete_evt+0xbc/0x13f0 net/bluetooth/hci_event.c:3117
 #3: ffff88801c6a5180 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x38/0x850 fs/kernfs/dir.c:826

stack backtrace:
CPU: 0 UID: 0 PID: 12412 Comm: kworker/u9:1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
 down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1625
 kernfs_link_sibling+0x555/0x850 fs/kernfs/dir.c:411
 kernfs_add_one+0x1e7/0x850 fs/kernfs/dir.c:845
 kernfs_create_dir_ns+0xfc/0x1a0 fs/kernfs/dir.c:1131
 sysfs_create_dir_ns+0x13a/0x2b0 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:73 [inline]
 kobject_add_internal+0x2c8/0x930 lib/kobject.c:240
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_add+0x16a/0x1e0 lib/kobject.c:426
 device_add+0x294/0x1950 drivers/base/core.c:3629
 hci_conn_add_sysfs+0x1a3/0x260 net/bluetooth/hci_sysfs.c:48
 hci_conn_complete_evt+0x5bb/0x13f0 net/bluetooth/hci_event.c:3200
 hci_event_func net/bluetooth/hci_event.c:7796 [inline]
 hci_event_packet+0x8e9/0xcd0 net/bluetooth/hci_event.c:7847
 hci_rx_work+0x451/0xfc0 net/bluetooth/hci_core.c:4077
 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302
 process_scheduled_works kernel/workqueue.c:3385 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (3277):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/09 09:04 upstream 70390501d194 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root possible deadlock in kernfs_link_sibling
2026/05/07 05:46 upstream 5862221fdded f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root possible deadlock in kernfs_link_sibling
2026/04/27 23:12 upstream 254f49634ee1 ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in kernfs_link_sibling
2026/04/25 15:12 upstream 27d128c1cff6 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in kernfs_link_sibling
2026/03/17 04:22 upstream 2d1373e4246d 0737c18f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in kernfs_link_sibling
2026/05/09 07:48 upstream cbf457c584b5 29233ece .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream possible deadlock in kernfs_link_sibling
2026/03/13 17:29 upstream 0257f64bdac7 351cb5cf .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream possible deadlock in kernfs_link_sibling
2026/04/25 17:37 upstream 27d128c1cff6 9c2d0995 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in kernfs_link_sibling
2026/05/10 02:18 net 496c0c4c53bb 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/10 01:14 net 496c0c4c53bb 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 22:44 net 496c0c4c53bb 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 22:39 net 496c0c4c53bb 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 19:59 net 496c0c4c53bb 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 16:43 net 496c0c4c53bb 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 14:53 net 496c0c4c53bb 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 11:46 net 496c0c4c53bb 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 06:14 net 58e2330bd455 0c5a8d8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 02:51 net 58e2330bd455 0c5a8d8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 01:35 net 58e2330bd455 0c5a8d8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 01:13 net 58e2330bd455 0c5a8d8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 23:48 net 58e2330bd455 0c5a8d8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 22:44 net fcee7d82f27d 0c5a8d8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 20:33 net fcee7d82f27d 0c5a8d8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 17:54 net fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 15:41 net fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 14:04 net fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 12:11 net fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 11:01 net fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 10:45 net fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 09:22 net fcee7d82f27d 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 03:58 net 41ae14071cd7 e358bca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 01:52 net 41ae14071cd7 e358bca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 21:28 net 41ae14071cd7 e358bca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 20:17 net 41ae14071cd7 e358bca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 18:57 net 41ae14071cd7 e358bca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 15:56 net b266bacba796 f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 13:17 net b266bacba796 f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 12:06 net b266bacba796 f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 10:17 net b266bacba796 f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 08:53 net b266bacba796 f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 07:49 net b266bacba796 f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 07:17 net b266bacba796 f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 23:53 net-next 8b2feced65cd 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 21:18 net-next 8b2feced65cd 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 18:48 net-next 8b2feced65cd 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 17:46 net-next 8b2feced65cd 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 15:34 net-next 8b2feced65cd 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 13:42 net-next 8b2feced65cd 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 12:19 net-next 8b2feced65cd 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/09 10:41 net-next 8b2feced65cd 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 07:53 net-next 6a4c4656b0d2 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/08 00:41 net-next 6a4c4656b0d2 e358bca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 23:03 net-next 6a4c4656b0d2 e358bca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/07 17:17 net-next dacf281771a9 e358bca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in kernfs_link_sibling
2026/05/05 00:03 linux-next 9d0d467c3572 a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in kernfs_link_sibling
2026/04/10 17:01 linux-next cc13002a9f98 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in kernfs_link_sibling
* Struck through repros no longer work on HEAD.