INFO: task kworker/1:1:28 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:1 state:D stack:20904 pid:28 tgid:28 ppid:2 task_flags:0x4288060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x1325/0x47d0 kernel/sched/core.c:7234 rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:752 Showing all locks held in the system: 5 locks held by kworker/0:0/9: 2 locks held by kworker/u8:0/12: #0: ffff8881000ac140 ( (wq_completion)events_unbound ){+.+.}-{0:0} , at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297 #1: ffffc900000cfd18 ((work_completion)(&(&wb->bw_dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 4 locks held by kworker/1:1/28: 1 lock held by khungtaskd/30: #0: ffffffff896e3000 ( rcu_read_lock ){....}-{1:3} , at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] , at: rcu_read_lock include/linux/rcupdate.h:840 [inline] , at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:1/32: #0: ffff8881000ac140 ( (wq_completion)events_unbound ){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297 #1: ffffc90000227d18 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 5 locks held by kworker/u8:3/45: #0: ffff888100e98940 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297 #1: ffffc90000507d18 (net_cleanup_work ){+.+.}-{0:0} , at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 #2: ffffffff8ab090e8 (pernet_ops_rwsem){++++}-{4:4} , at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:673 #3: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline] (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248 #4: ffffffff896eeaa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 2 locks held by kworker/u8:7/344: #0: ffff8881000ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: raw_spin_rq_lock_nested kernel/sched/core.c:667 [inline] ((wq_completion)events_unbound){+.+.}-{0:0}, at: raw_spin_rq_lock kernel/sched/sched.h:1653 [inline] ((wq_completion)events_unbound){+.+.}-{0:0}, at: rq_lock kernel/sched/sched.h:1991 [inline] ((wq_completion)events_unbound){+.+.}-{0:0}, at: __schedule+0x2dc/0x47d0 kernel/sched/core.c:7108 #1: ffffc90001d1fd18 ((stats_flush_dwork).work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 2 locks held by getty/2917: #0: ffff8881126180a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000452e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211 4 locks held by udevd/5201: #0: ffff8881082ade18 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff8881133e1480 (&of->mutex){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165 #2: ffff888113723f08 (kn->active#9){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888113723f08 (kn->active#9){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:166 #3: ffff88811e1371d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1107 [inline] #3: ffff88811e1371d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 3 locks held by kworker/1:4/5222: #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297 #1: ffffc9000221fd18 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 #2: ffffffff896eeaa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 6 locks held by kworker/0:4/5241: #0: ffff888105ae7940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297 #1: ffffc900022dfd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 #2: ffff8881093741d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #2: ffff8881093741d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88811e1371d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #3: ffff88811e1371d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336 #4: ffff8881188031a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #4: ffff8881188031a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline] #4: ffff8881188031a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369 #5: ffffffff8a53fae0 (input_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8a53fae0 (input_mutex){+.+.}-{4:4}, at: __input_unregister_device+0x138/0x4d0 drivers/input/input.c:2204 2 locks held by syz-executor/6234: #0: ffffffff8ab090e8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575 #1: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline] #1: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248 2 locks held by syz-executor/6251: #0: ffffffff8ab090e8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575 #1: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline] #1: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248 2 locks held by syz-executor/6271: #0: ffffffff8ab090e8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575 #1: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline] #1: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248 1 lock held by syz-executor/6331: #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8bb/0x2210 net/core/rtnetlink.c:4158 1 lock held by syz-executor/6341: #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8bb/0x2210 net/core/rtnetlink.c:4158 1 lock held by syz-executor/6351: #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8bb/0x2210 net/core/rtnetlink.c:4158 1 lock held by syz-executor/6361: #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8bb/0x2210 net/core/rtnetlink.c:4158 1 lock held by syz-executor/6371: #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8ab21b00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8bb/0x2210 net/core/rtnetlink.c:4158 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xcb1/0x1030 kernel/hung_task.c:561 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5361 Comm: kworker/0:6 Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events free_obj_work RIP: 0010:unwind_next_frame+0x52e/0x2090 arch/x86/kernel/unwind_orc.c:527 Code: 48 b8 00 00 00 00 00 fc ff df 4c 89 c2 48 c1 ee 03 48 c1 ea 03 0f b6 14 02 0f b6 04 06 4c 89 c6 83 e6 07 40 38 f2 40 0f 9e c6 <84> d2 0f 95 c2 40 84 d6 0f 85 d7 14 00 00 41 83 e7 07 44 38 f8 0f RSP: 0018:ffffc90003b6f710 EFLAGS: 00000297 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff8b5835b0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8b016e74 RBP: ffffc90003b6f7c8 R08: ffffffff8b5835b4 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000007dc8 R12: ffffc90003b6f7d0 R13: ffffc90003b6f780 R14: ffffc90003b6f7b5 R15: ffffffff8b5835b5 FS: 0000000000000000(0000) GS:ffff888268640000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7b5bb61048 CR3: 00000001164d6000 CR4: 00000000003506f0 Call Trace: arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x43/0x70 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2705 [inline] slab_free mm/slub.c:6405 [inline] kmem_cache_free+0x108/0x650 mm/slub.c:6532 free_object_list.isra.0+0xf8/0x2a0 lib/debugobjects.c:326 free_obj_work+0x18c/0x390 lib/debugobjects.c:530 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245