INFO: task kworker/1:4:5230 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:4 state:D stack:21112 pid:5230 tgid:5230 ppid:2 task_flags:0x4288060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0xf89/0x4840 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 lbs_wait_for_firmware_load+0x11e/0x1e0 drivers/net/wireless/marvell/libertas/firmware.c:116 lbs_remove_card+0x84/0x390 drivers/net/wireless/marvell/libertas/main.c:913 if_usb_disconnect+0xad/0x260 drivers/net/wireless/marvell/libertas/if_usb.c:316 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:1352 [inline] device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1375 bus_remove_device+0x2bc/0x560 drivers/base/bus.c:657 device_del+0x376/0x9b0 drivers/base/core.c:3895 usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1478 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+0x69a/0xc80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff896de8e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff896de8e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff896de8e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 2 locks held by kworker/0:2/368: #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc9000205fd18 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 2 locks held by getty/2921: #0: ffff8881165920a0 (&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+0x419/0x14f0 drivers/tty/n_tty.c:2211 5 locks held by kworker/1:4/5230: #0: ffff888106290540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc9000231fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810c3431d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88810c3431d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff8881155b61d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff8881155b61d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336 #4: ffff88813d29d1a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88813d29d1a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1174 [inline] #4: ffff88813d29d1a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1372 8 locks held by kworker/1:5/5236: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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: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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 2839 Comm: syslogd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:mark_lock+0x6/0xa20 kernel/locking/lockdep.c:4714 Code: 5d 89 e8 dd 6b 98 ff e9 5c fd ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 <41> 56 41 55 49 89 fd 41 54 49 89 f4 53 48 83 e4 f0 48 83 ec 70 65 RSP: 0018:ffffc900015378b8 EFLAGS: 00000002 RAX: 0000000000000004 RBX: ffff8881176e8b48 RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffff8881176e8b48 RDI: ffff8881176e8000 RBP: ffffc900015378c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000002 R13: ffff8881176e8000 R14: ffffffff8647a489 R15: 0000000000000000 FS: 00007f83e98bcc80(0000) GS:ffff8882687a8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1f86b2a4c0 CR3: 000000011774a000 CR4: 00000000003506f0 Call Trace: mark_held_locks+0x40/0x70 kernel/locking/lockdep.c:4325 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4343 [inline] lockdep_hardirqs_on_prepare kernel/locking/lockdep.c:4410 [inline] lockdep_hardirqs_on_prepare+0xb4/0x1b0 kernel/locking/lockdep.c:4362 trace_hardirqs_on+0x36/0x40 kernel/trace/trace_preemptirq.c:78 kasan_quarantine_put+0x104/0x240 mm/kasan/quarantine.c:234 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6246 [inline] kfree+0x204/0x650 mm/slub.c:6561 skb_kfree_head net/core/skbuff.c:1075 [inline] skb_free_head+0xb9/0x160 net/core/skbuff.c:1087 skb_release_data+0x6c5/0x8e0 net/core/skbuff.c:1114 skb_release_all net/core/skbuff.c:1189 [inline] __kfree_skb net/core/skbuff.c:1203 [inline] consume_skb net/core/skbuff.c:1436 [inline] consume_skb+0xc4/0x110 net/core/skbuff.c:1430 __unix_dgram_recvmsg+0x754/0xc30 net/unix/af_unix.c:2669 unix_dgram_recvmsg+0xcd/0x100 net/unix/af_unix.c:2686 sock_recvmsg_nosec net/socket.c:1137 [inline] sock_recvmsg+0x1a4/0x1f0 net/socket.c:1159 sock_read_iter+0x2c6/0x3c0 net/socket.c:1229 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x957/0xb30 fs/read_write.c:574 ksys_read+0x1f8/0x250 fs/read_write.c:717 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0x7f0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f83e9a0c407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007fff08839070 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f83e98bcc80 RCX: 00007f83e9a0c407 RDX: 00000000000000ff RSI: 000055b161247300 RDI: 0000000000000000 RBP: 000055b1612472c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055b16124734c R13: 0000000000000000 R14: 000055b161247300 R15: 000055b160c15d98