INFO: task kworker/1:8:23527 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:8 state:D stack:22200 pid:23527 tgid:23527 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ef/0x4fb0 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x164/0x360 kernel/sched/core.c:6964 usb_kill_urb+0x1cf/0x2f0 drivers/usb/core/urb.c:718 usb_start_wait_urb+0x1a3/0x510 drivers/usb/core/message.c:65 usb_internal_control_msg drivers/usb/core/message.c:103 [inline] usb_control_msg+0x232/0x3e0 drivers/usb/core/message.c:154 get_bMaxPacketSize0 drivers/usb/core/hub.c:4851 [inline] hub_port_init+0xb1e/0x28d0 drivers/usb/core/hub.c:5047 hub_port_connect drivers/usb/core/hub.c:5496 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x2593/0x4f30 drivers/usb/core/hub.c:5953 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0x89f/0xd90 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5594: #0: ffff88803523d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 5 locks held by kworker/1:8/23527: #0: ffff888142e89d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff888142e89d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc9001688fbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9001688fbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffff888029936198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #2: ffff888029936198 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899 #3: ffff888029b46518 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff888029b46518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #3: ffff888029b46518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #3: ffff888029b46518 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #3: ffff888029b46518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x217a/0x4f30 drivers/usb/core/hub.c:5953 #4: ffff888143f61468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline] #4: ffff888143f61468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #4: ffff888143f61468 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #4: ffff888143f61468 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21a2/0x4f30 drivers/usb/core/hub.c:5953 2 locks held by syz.6.8899/13811: 1 lock held by syz.5.8901/13828: 1 lock held by syz.4.8902/13834: 5 locks held by syz.4.8902/13837: 2 locks held by syz.0.8903/13839: #0: ffffffff8f7a8808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f7a8808 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x722/0xbe0 net/core/rtnetlink.c:6964 #1: ffffffff8e360c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #1: ffffffff8e360c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:956 1 lock held by syz.0.8903/13840: #0: ffffffff8f7a8808 (rtnl_mutex){+.+.}-{4:4}, at: tc_new_tfilter+0x4ff/0x1630 net/sched/cls_api.c:2308 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 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+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xf90/0xfe0 kernel/hung_task.c:515 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13838 Comm: syz.0.8903 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline] RIP: 0010:lock_acquire+0x116/0x330 kernel/locking/lockdep.c:5870 Code: 8b 54 24 04 44 89 e1 45 89 f0 6a 00 6a 00 6a 00 55 ff 74 24 30 e8 ba 02 00 00 48 83 c4 28 48 c7 c7 62 92 d3 8d e8 4a 98 d9 09 ff ff ff ff 65 0f c1 05 9d 93 30 11 83 f8 01 0f 85 ae 00 00 00 RSP: 0018:ffffc90016827808 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000ddd44900 RSI: ffffffff8dd39262 RDI: ffffffff8be73880 RBP: ffffffff8210cf9f R08: ffffffff8210cf9f R09: ffff888031a9a800 R10: ffffc90016827960 R11: fffff52002d04f2f R12: 0000000000000001 R13: ffff888031a9a800 R14: 0000000000000001 R15: 0000000000000246 FS: 0000000000000000(0000) GS:ffff888125a28000(0063) knlGS:00000000f53b5b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000080043018 CR3: 000000009e05a000 CR4: 00000000003526f0 Call Trace: __might_fault+0xcb/0x130 mm/memory.c:7177 _inline_copy_from_user include/linux/uaccess.h:169 [inline] _copy_from_user+0x28/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] get_compat_msghdr+0xb3/0x4c0 net/compat.c:91 recvmsg_copy_msghdr net/socket.c:2776 [inline] ___sys_recvmsg+0x1dd/0x590 net/socket.c:2850 do_recvmmsg+0x3a5/0x800 net/socket.c:2941 __sys_recvmmsg+0x1a5/0x290 net/socket.c:3023 __do_compat_sys_recvmmsg_time32 net/compat.c:418 [inline] __se_compat_sys_recvmmsg_time32 net/compat.c:414 [inline] __ia32_compat_sys_recvmmsg_time32+0xbf/0xe0 net/compat.c:414 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1d2/0x540 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f12539 Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f53b550c EFLAGS: 00000206 ORIG_RAX: 0000000000000151 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000800000c0 RDX: 0000000000010106 RSI: 0000000000000002 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000