INFO: task udevd:4284 blocked for more than 143 seconds. Not tainted 6.1.146-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:25792 pid:4284 ppid:3637 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747 device_lock include/linux/device.h:837 [inline] uevent_show+0x16c/0x320 drivers/base/core.c:2669 dev_attr_show+0x50/0xb0 drivers/base/core.c:2372 sysfs_kf_seq_show+0x349/0x4b0 fs/sysfs/file.c:59 seq_read_iter+0x49b/0xd50 fs/seq_file.c:230 call_read_iter include/linux/fs.h:2259 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x434/0x920 fs/read_write.c:470 ksys_read+0x143/0x240 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f49fcea7407 RSP: 002b:00007ffe489fe8c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f49fd579880 RCX: 00007f49fcea7407 RDX: 0000000000001000 RSI: 00005605145e3a10 RDI: 0000000000000008 RBP: 00007f49fcfefff0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a R13: 00007f49fcfefea0 R14: 0000000000000000 R15: 00005605145f6220 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2b7b0 (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: ffffffff8cb2bfd0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 6 locks held by kworker/1:1/26: #0: ffff88801c2dbd38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90000a1fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffff88814674d190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #2: ffff88814674d190 (&dev->mutex){....}-{3:3}, at: hub_event+0x185/0x5210 drivers/usb/core/hub.c:5813 #3: ffff88805a216190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #3: ffff88805a216190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:990 #4: ffff888059101118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #4: ffff888059101118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:990 #5: ffffffff8c9d79b0 (umhelper_sem){++++}-{3:3}, at: usermodehelper_read_trylock+0xec/0x2a0 kernel/umh.c:218 1 lock held by khungtaskd/28: #0: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 1 lock held by klogd/3626: #0: ffff8880b8e3aa98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:545 2 locks held by getty/4024: #0: ffff888030309098 (&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 4 locks held by udevd/4284: #0: ffff88802ca4ce80 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182 #1: ffff888029584888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x51/0x3b0 fs/kernfs/file.c:154 #2: ffff888056d701d8 (kn->active#5){.+.+}-{0:0}, at: kernfs_seq_start+0x71/0x3b0 fs/kernfs/file.c:155 #3: ffff88805a216190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #3: ffff88805a216190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2669 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.146-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4413 Comm: kworker/u4:10 Not tainted 6.1.146-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: phy7 ieee80211_iface_work RIP: 0010:__lock_acquire+0xe2c/0x7c50 kernel/locking/lockdep.c:5027 Code: 3c 00 00 74 12 48 89 df e8 a1 e5 6d 00 49 b8 00 00 00 00 00 fc ff df 48 89 9c 24 c0 00 00 00 4c 8b 2b 48 83 7c 24 60 00 75 31 <48> c7 c0 20 41 be 96 48 c1 e8 03 42 0f b6 04 00 84 c0 0f 85 99 5d RSP: 0018:ffffc900049bf8a0 EFLAGS: 00000046 RAX: 1ffff1100f9ee8ca RBX: ffff88807cf74650 RCX: ffffffff8162fd66 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90add340 RBP: ffffc900049bfaf0 R08: dffffc0000000000 R09: fffffbfff215ba69 R10: fffffbfff215ba69 R11: 1ffffffff215ba68 R12: ffff88807cf73b80 R13: ffffffffffffffff R14: ffff88807cf74660 R15: ffff88807cf73b80 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8adf7802d8 CR3: 000000000c88e000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 process_one_work+0x7b7/0x1160 kernel/workqueue.c:2267 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