INFO: task kworker/0:1:14 blocked for more than 146 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:1 state:D stack:21408 pid:14 ppid:2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 usb_kill_urb+0x1c2/0x2f0 drivers/usb/core/urb.c:728 usb_start_wait_urb+0x189/0x4b0 drivers/usb/core/message.c:64 usb_internal_control_msg drivers/usb/core/message.c:102 [inline] usb_control_msg+0x22f/0x3e0 drivers/usb/core/message.c:153 get_bMaxPacketSize0 drivers/usb/core/hub.c:4798 [inline] hub_port_init+0xcd3/0x2ac0 drivers/usb/core/hub.c:4995 hub_port_connect drivers/usb/core/hub.c:5446 [inline] hub_port_connect_change drivers/usb/core/hub.c:5657 [inline] port_event drivers/usb/core/hub.c:5817 [inline] hub_event+0x292c/0x54e0 drivers/usb/core/hub.c:5899 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2b370 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8cb2bb90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 5 locks held by kworker/0:1/14: #0: ffff88801768a938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90000137d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffff888028e32190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #2: ffff888028e32190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1a7/0x54e0 drivers/usb/core/hub.c:5845 #3: ffff888028e724f8 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3200 [inline] #3: ffff888028e724f8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5413 [inline] #3: ffff888028e724f8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5657 [inline] #3: ffff888028e724f8 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5817 [inline] #3: ffff888028e724f8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x21bd/0x54e0 drivers/usb/core/hub.c:5899 #4: ffff88801efe2d68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5414 [inline] #4: ffff88801efe2d68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5657 [inline] #4: ffff88801efe2d68 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5817 [inline] #4: ffff88801efe2d68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x21ee/0x54e0 drivers/usb/core/hub.c:5899 1 lock held by khungtaskd/27: #0: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2a9e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 2 locks held by getty/4026: #0: ffff88814d15d098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198 2 locks held by kworker/u4:10/4419: #0: ffff8880b8e3aa98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:545 #1: ffff8880b8e27848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999 1 lock held by syz-executor/9879: #0: ffffffff8cb306b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] #0: ffffffff8cb306b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962 2 locks held by kworker/1:5/14412: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90003297d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4759 Comm: kworker/u4:17 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:put_cpu_partial+0xc7/0x250 mm/slub.c:2639 Code: 0c 49 83 7c 24 28 00 0f 85 0a 01 00 00 65 4c 8b 35 0e fd 31 7e 4d 89 74 24 28 48 8b 03 65 48 8b 40 18 48 85 c0 74 19 8b 48 10 <83> 7c 24 04 00 74 05 3b 4b 30 73 0f ff c1 45 31 e4 41 89 cd eb 0a RSP: 0018:ffffc90005887910 EFLAGS: 00000086 RAX: ffffea000187d700 RBX: ffff8881401e8500 RCX: 0000000000000003 RDX: 0000000000000000 RSI: ffffffff8a8c1480 RDI: ffffffff8adefae0 RBP: 0000000000000082 R08: dffffc0000000000 R09: fffffbfff215c249 R10: fffffbfff215c249 R11: 1ffffffff215c248 R12: ffff8880b8e431a0 R13: 0000000000000001 R14: ffff888078c98000 R15: ffffea000076d5c0 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efc23393ad8 CR3: 0000000020f78000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: get_partial_node+0x1b7/0x470 mm/slub.c:2234 get_partial mm/slub.c:2325 [inline] ___slab_alloc+0x968/0x1220 mm/slub.c:3175 __slab_alloc mm/slub.c:3279 [inline] slab_alloc_node mm/slub.c:3364 [inline] kmem_cache_alloc_node+0x1e5/0x320 mm/slub.c:3443 __alloc_skb+0xfc/0x7e0 net/core/skbuff.c:505 alloc_skb include/linux/skbuff.h:1271 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x28f/0xaf0 drivers/net/netdevsim/dev.c:851 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295