INFO: task kworker/0:2:737 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:2 state:D stack:21192 pid:737 tgid:737 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xeb1/0x4220 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7008 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065 rwsem_down_write_slowpath+0x530/0x1280 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1c7/0x1f0 kernel/locking/rwsem.c:1591 kernfs_add_one+0x38/0x850 fs/kernfs/dir.c:796 kernfs_create_dir_ns+0xfc/0x1a0 fs/kernfs/dir.c:1098 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 Showing all locks held in the system: 4 locks held by kworker/0:1/10: 1 lock held by khungtaskd/29: #0: ffffffff896de6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] ffffffff896de6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] ffffffff896de6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 3 locks held by kworker/1:1/41: #0: ffff88810006b148 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251 #1: ffffc900002b7d18 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252 #2: ffffffff896ea2f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 2 locks held by kworker/u8:5/142: #0: ffff8881000ac948 ((wq_completion)events_unbound #2){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251 #1: ffffc90001597d18 ((work_completion)(&sub_info->work) ){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252 3 locks held by kworker/1:2/249: #0: ffff88810006b148 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251 #1: ffffc900016a7d18 (drain_vmap_work ){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252 #2: ffffffff8988e808 (vmap_purge_lock){+.+.}-{4:4}, at: drain_vmap_area_work+0x17/0x40 mm/vmalloc.c:2435 4 locks held by kworker/0:2/737: 4 locks held by kworker/u8:12/2668: #0: ffff888101299148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251 #1: ffffc900049ffd18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252 #2: ffffffff8aae1bf0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xb8/0x9e0 net/core/net_namespace.c:675 #3: ffffffff8aafa128 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline] #3: ffffffff8aafa128 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248 2 locks held by getty/2920: #0: ffff88811293d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211 1 lock held by udevd/5221: #0: ffff8881f5739620 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:647 [inline] #0: ffff8881f5739620 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1615 [inline] #0: ffff8881f5739620 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1946 [inline] #0: ffff8881f5739620 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x2ca/0x4220 kernel/sched/core.c:6814 2 locks held by kworker/0:4/5230: 6 locks held by kworker/1:5/5243: #0: ffff888102ab4d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251 #1: ffffc900029b7d18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252 #2: ffff88810abf8198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #2: ffff88810abf8198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88810abfd510 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff88810abfd510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #3: ffff88810abfd510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #3: ffff88810abfd510 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #3: ffff88810abfd510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x2bd2/0x4af0 drivers/usb/core/hub.c:5953 #4: ffff88810ab7a468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline] #4: ffff88810ab7a468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #4: ffff88810ab7a468 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #4: ffff88810ab7a468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2bfb/0x4af0 drivers/usb/core/hub.c:5953 #5: ffffffff8a2f1bf0 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x1a5/0x1c60 drivers/usb/core/hub.c:3067 1 lock held by udevd/5438: #0: ffffffff896ea2f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 6 locks held by kworker/0:6/5462: #0: ffff888102ab4d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251 #1: ffffc9000308fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252 #2: ffff88810af10198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #2: ffff88810af10198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88810af15510 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff88810af15510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #3: ffff88810af15510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #3: ffff88810af15510 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #3: ffff88810af15510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x2bd2/0x4af0 drivers/usb/core/hub.c:5953 #4: ffff88810abdd368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline] #4: ffff88810abdd368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #4: ffff88810abdd368 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #4: ffff88810abdd368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2bfb/0x4af0 drivers/usb/core/hub.c:5953 #5: ffffffff8a2f1bf0 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x1a5/0x1c60 drivers/usb/core/hub.c:3067 2 locks held by syz-executor/5478: #0: ffffffff8aae1bf0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aafa128 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline] #1: ffffffff8aafa128 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x50 net/core/dev.c:11537 1 lock held by syz-executor/5506: #0: ffffffff8aafa128 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8aafa128 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x18b0 net/ipv4/devinet.c:978 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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:113 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline] watchdog+0xd25/0x1050 kernel/hung_task.c:515 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5516 Comm: modprobe Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x18/0x90 kernel/kcov.c:246 Code: 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 8b 05 19 42 43 0b 49 89 f8 49 89 f1 49 89 d2 65 48 8b 3d f0 41 43 0b 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 c3 cc cc RSP: 0018:ffffc90004ecf140 EFLAGS: 00000202 RAX: 0000000080000000 RBX: 000000000000000a RCX: ffffffff87621c26 RDX: 000000000000000a RSI: 000000000000000a RDI: ffff8881127f8000 RBP: 0000000000000003 R08: 0000000000000004 R09: 000000000000000a R10: 000000000000000a R11: 0000000000000000 R12: ffffffff88881e83 R13: 000000000000000a R14: dffffc0000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8882687ce000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8c1ff514e8 CR3: 000000011b580000 CR4: 00000000003506f0 Call Trace: mas_validate_parent_slot lib/maple_tree.c:6981 [inline] mt_validate+0x906/0x30b0 lib/maple_tree.c:7172 validate_mm+0xa8/0x4e0 mm/vma.c:649 __split_vma+0xa46/0xd60 mm/vma.c:567 vms_gather_munmap_vmas+0x39f/0x1480 mm/vma.c:1429 __mmap_setup mm/vma.c:2411 [inline] __mmap_region+0x491/0x26e0 mm/vma.c:2741 mmap_region+0x180/0x3e0 mm/vma.c:2837 do_mmap+0xc53/0x12d0 mm/mmap.c:559 vm_mmap_pgoff+0x201/0x390 mm/util.c:581 ksys_mmap_pgoff+0x3c8/0x650 mm/mmap.c:605 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline] __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0x7b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8c1ff82242 Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00 RSP: 002b:00007fffd179a2e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f8c1fe81000 RCX: 00007f8c1ff82242 RDX: 0000000000000003 RSI: 0000000000006000 RDI: 00007f8c1fe81000 RBP: 0000000000000812 R08: 0000000000000000 R09: 00000000001cc000 R10: 0000000000000812 R11: 0000000000000206 R12: 00007fffd179a3a8 R13: 00007f8c1ff565f0 R14: 00007fffd179ab20 R15: 00000ffffa2f3460