input: PWC snapshot button as /devices/platform/dummy_hcd.3/usb4/4-1/input/input25 usb 4-1: USB disconnect, device number 20 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ kworker/1:6/6009 is trying to acquire lock: ffff88801c6b52a0 (&root->kernfs_supers_rwsem){++++}-{4:4}, at: kernfs_remove fs/kernfs/dir.c:1623 [inline] ffff88801c6b52a0 (&root->kernfs_supers_rwsem){++++}-{4:4}, at: kernfs_remove+0x3b/0x70 fs/kernfs/dir.c:1614 but task is already holding lock: ffffffff8f768860 (gdp_mutex){+.+.}-{4:4}, at: cleanup_glue_dir drivers/base/core.c:3365 [inline] ffffffff8f768860 (gdp_mutex){+.+.}-{4:4}, at: cleanup_glue_dir+0xcd/0x260 drivers/base/core.c:3357 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #11 (gdp_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 get_device_parent+0xff/0x4c0 drivers/base/core.c:3268 device_add+0xc36/0x1920 drivers/base/core.c:3615 device_create_groups_vargs+0x1f8/0x270 drivers/base/core.c:4373 device_create+0xed/0x130 drivers/base/core.c:4412 msr_device_create+0x31/0x70 arch/x86/kernel/msr.c:251 cpuhp_invoke_callback+0x3ab/0x9a0 kernel/cpu.c:194 cpuhp_thread_fun+0x3e9/0x7c0 kernel/cpu.c:1109 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160 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 -> #10 (cpuhp_state-up){+.+.}-{0:0}: cpuhp_lock_acquire kernel/cpu.c:103 [inline] cpuhp_thread_fun+0x146/0x7c0 kernel/cpu.c:1086 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160 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 -> #9 (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 udp_tunnel_encap_enable include/net/udp_tunnel.h:232 [inline] setup_udp_tunnel_sock+0x4f9/0x620 net/ipv4/udp_tunnel_core.c:92 l2tp_tunnel_register+0x9e5/0xbe0 net/l2tp/l2tp_core.c:1686 pppol2tp_tunnel_get.constprop.0+0x3f0/0x540 net/l2tp/l2tp_ppp.c:662 pppol2tp_connect+0xaf0/0x1c20 net/l2tp/l2tp_ppp.c:710 __sys_connect_file+0x141/0x1a0 net/socket.c:2148 __sys_connect+0x141/0x170 net/socket.c:2167 __do_sys_connect net/socket.c:2173 [inline] __se_sys_connect net/socket.c:2170 [inline] __x64_sys_connect+0x72/0xb0 net/socket.c:2170 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 -> #8 (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 recv_work+0x5fb/0x8c0 drivers/block/nbd.c:1021 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 -> #7 (&nsock->tx_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 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:2730 submit_bh fs/buffer.c:2735 [inline] block_read_full_folio+0x4c8/0x8e0 fs/buffer.c:2351 filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2501 do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4106 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 -> #6 (&cmd->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 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:2730 submit_bh fs/buffer.c:2735 [inline] block_read_full_folio+0x4c8/0x8e0 fs/buffer.c:2351 filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2501 do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4106 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 (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 -> #4 (&q->elevator_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 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 -> #3 (&q->q_usage_counter(io)#50){++++}-{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 -> #2 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:4327 [inline] fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4341 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_lru_noprof+0x51/0x6e0 mm/slub.c:4917 alloc_inode+0x183/0x250 fs/inode.c:347 iget_locked+0x1d9/0x6d0 fs/inode.c:1474 kernfs_get_inode+0x46/0x470 fs/kernfs/inode.c:252 kernfs_fill_super fs/kernfs/mount.c:308 [inline] kernfs_get_tree+0x63e/0xbb0 fs/kernfs/mount.c:392 sysfs_get_tree+0x41/0x140 fs/sysfs/mount.c:31 vfs_get_tree+0x92/0x320 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3758 [inline] do_new_mount fs/namespace.c:3834 [inline] path_mount+0x7d0/0x23d0 fs/namespace.c:4154 do_mount fs/namespace.c:4167 [inline] __do_sys_mount fs/namespace.c:4383 [inline] __se_sys_mount fs/namespace.c:4360 [inline] __x64_sys_mount+0x293/0x310 fs/namespace.c:4360 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 -> #1 (&root->kernfs_rwsem){++++}-{4:4}: down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1625 kernfs_remove_by_name_ns+0x51/0x120 fs/kernfs/dir.c:1793 sysfs_remove_file include/linux/sysfs.h:780 [inline] device_remove_file drivers/base/core.c:3072 [inline] device_remove_file drivers/base/core.c:3068 [inline] device_links_driver_bound+0xed/0x950 drivers/base/core.c:1326 driver_bound+0xf0/0x220 drivers/base/dd.c:458 really_probe+0x3d4/0xa60 drivers/base/dd.c:759 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:851 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:881 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1009 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1081 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1136 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x11d9/0x1920 drivers/base/core.c:3691 faux_device_create_with_groups+0x1c6/0x2f0 drivers/base/faux.c:158 regulator_dummy_init+0x1e/0x40 drivers/regulator/dummy.c:67 regulator_init+0x14e/0x180 drivers/regulator/core.c:6772 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 -> #0 (&root->kernfs_supers_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_read+0x99/0x450 kernel/locking/rwsem.c:1568 kernfs_remove fs/kernfs/dir.c:1623 [inline] kernfs_remove+0x3b/0x70 fs/kernfs/dir.c:1614 sysfs_remove_dir+0xc8/0x110 fs/sysfs/dir.c:101 __kobject_del+0xe2/0x220 lib/kobject.c:604 kobject_del lib/kobject.c:627 [inline] kobject_del+0x3f/0x60 lib/kobject.c:619 cleanup_glue_dir drivers/base/core.c:3416 [inline] cleanup_glue_dir+0x203/0x260 drivers/base/core.c:3357 device_del+0x63b/0x9b0 drivers/base/core.c:3901 device_unregister+0x1d/0xe0 drivers/base/core.c:3921 video_unregister_device drivers/media/v4l2-core/v4l2-dev.c:1130 [inline] video_unregister_device+0xb3/0xd0 drivers/media/v4l2-core/v4l2-dev.c:1117 usb_pwc_disconnect+0xea/0x180 drivers/media/usb/pwc/pwc-if.c:1183 usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458 device_remove drivers/base/dd.c:621 [inline] device_remove+0x12a/0x180 drivers/base/dd.c:613 __device_release_driver drivers/base/dd.c:1332 [inline] device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1355 bus_remove_device+0x2bc/0x560 drivers/base/bus.c:657 device_del+0x376/0x9b0 drivers/base/core.c:3880 usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1476 usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2345 hub_port_connect drivers/usb/core/hub.c:5407 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x1d0c/0x4af0 drivers/usb/core/hub.c:5953 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_supers_rwsem --> cpuhp_state-up --> gdp_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(gdp_mutex); lock(cpuhp_state-up); lock(gdp_mutex); rlock(&root->kernfs_supers_rwsem); *** DEADLOCK *** 8 locks held by kworker/1:6/6009: #0: ffff8880222b2540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc9000201fd08 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88802abbb1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline] #2: ffff88802abbb1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff888020ee01d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline] #3: ffff888020ee01d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336 #4: ffff8880293601a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline] #4: ffff8880293601a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1154 [inline] #4: ffff8880293601a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1352 #5: ffff888027d50ac8 (&pdev->vb_queue_lock){+.+.}-{4:4}, at: usb_pwc_disconnect+0x5c/0x180 drivers/media/usb/pwc/pwc-if.c:1175 #6: ffff888027d50a40 (&pdev->v4l2_lock){+.+.}-{4:4}, at: usb_pwc_disconnect+0x66/0x180 drivers/media/usb/pwc/pwc-if.c:1176 #7: ffffffff8f768860 (gdp_mutex){+.+.}-{4:4}, at: cleanup_glue_dir drivers/base/core.c:3365 [inline] #7: ffffffff8f768860 (gdp_mutex){+.+.}-{4:4}, at: cleanup_glue_dir+0xcd/0x260 drivers/base/core.c:3357 stack backtrace: CPU: 1 UID: 0 PID: 6009 Comm: kworker/1:6 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: usb_hub_wq hub_event Call Trace: __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_read+0x99/0x450 kernel/locking/rwsem.c:1568 kernfs_remove fs/kernfs/dir.c:1623 [inline] kernfs_remove+0x3b/0x70 fs/kernfs/dir.c:1614 sysfs_remove_dir+0xc8/0x110 fs/sysfs/dir.c:101 __kobject_del+0xe2/0x220 lib/kobject.c:604 kobject_del lib/kobject.c:627 [inline] kobject_del+0x3f/0x60 lib/kobject.c:619 cleanup_glue_dir drivers/base/core.c:3416 [inline] cleanup_glue_dir+0x203/0x260 drivers/base/core.c:3357 device_del+0x63b/0x9b0 drivers/base/core.c:3901 device_unregister+0x1d/0xe0 drivers/base/core.c:3921 video_unregister_device drivers/media/v4l2-core/v4l2-dev.c:1130 [inline] video_unregister_device+0xb3/0xd0 drivers/media/v4l2-core/v4l2-dev.c:1117 usb_pwc_disconnect+0xea/0x180 drivers/media/usb/pwc/pwc-if.c:1183 usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458 device_remove drivers/base/dd.c:621 [inline] device_remove+0x12a/0x180 drivers/base/dd.c:613 __device_release_driver drivers/base/dd.c:1332 [inline] device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1355 bus_remove_device+0x2bc/0x560 drivers/base/bus.c:657 device_del+0x376/0x9b0 drivers/base/core.c:3880 usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1476 usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2345 hub_port_connect drivers/usb/core/hub.c:5407 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x1d0c/0x4af0 drivers/usb/core/hub.c:5953 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