INFO: task udevd:5841 blocked for more than 143 seconds. Not tainted 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:25624 pid:5841 tgid:5841 ppid:5199 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:746 device_lock include/linux/device.h:922 [inline] uevent_show+0x174/0x330 drivers/base/core.c:2730 dev_attr_show+0x55/0xc0 drivers/base/core.c:2424 sysfs_kf_seq_show+0x30d/0x490 fs/sysfs/file.c:65 seq_read_iter+0x4e7/0xe10 fs/seq_file.c:230 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x4cd/0x980 fs/read_write.c:570 ksys_read+0x145/0x250 fs/read_write.c:713 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f13bd516b6a RSP: 002b:00007ffc8c2e76f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000055973aa69b50 RCX: 00007f13bd516b6a RDX: 0000000000001000 RSI: 000055973aa6c700 RDI: 0000000000000008 RBP: 000055973aa69b50 R08: 0000000000000008 R09: 0000000000000008 R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000003fff R14: 00007ffc8c2e7bd8 R15: 000000000000000a Showing all locks held in the system: 5 locks held by kworker/0:1/10: #0: ffff8881452ee548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff8881452ee548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc900000f7c60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc900000f7c60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffff88802766b198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #2: ffff88802766b198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a00 drivers/usb/core/hub.c:5859 #3: ffff88805cf6c198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #3: ffff88805cf6c198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1005 #4: ffff888059ad1160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #4: ffff888059ad1160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1005 3 locks held by kworker/u8:1/13: #0: ffff8880b8839b58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:613 #1: ffff8880b8923b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987 #2: ffffffff8df3b8c0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #2: ffffffff8df3b8c0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:892 [inline] #2: ffffffff8df3b8c0 (rcu_read_lock_bh){....}-{1:3}, at: mod_peer_timer+0x21/0x260 drivers/net/wireguard/timers.c:34 1 lock held by khungtaskd/31: #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 7 locks held by kworker/u8:6/3450: 2 locks held by getty/5577: #0: ffff8880325480a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 4 locks held by udevd/5821: #0: ffff88805904ac30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:182 #1: ffff888058d43888 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:154 #2: ffff888026e99968 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x75/0x3c0 fs/kernfs/file.c:155 #3: ffff888011ccc198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #3: ffff888011ccc198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x174/0x330 drivers/base/core.c:2730 4 locks held by udevd/5841: #0: ffff88802cb39c30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:182 #1: ffff888028397488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:154 #2: ffff88802fa334b8 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x75/0x3c0 fs/kernfs/file.c:155 #3: ffff88805cf6c198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #3: ffff88805cf6c198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x174/0x330 drivers/base/core.c:2730 6 locks held by kworker/0:4/5880: #0: ffff8881452ee548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff8881452ee548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc9000489fc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000489fc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffff888145f1b198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #2: ffff888145f1b198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a00 drivers/usb/core/hub.c:5859 #3: ffff888011ccc198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #3: ffff888011ccc198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1005 #4: ffff888056de0160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #4: ffff888056de0160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1005 #5: ffffffff8f2814a8 (register_mutex#6){+.+.}-{4:4}, at: usb_audio_probe+0x390/0x1dc0 sound/usb/card.c:813 5 locks held by kworker/0:5/5887: #0: ffff8881452ee548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff8881452ee548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc900048ffc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc900048ffc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffff88802760b198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #2: ffff88802760b198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a00 drivers/usb/core/hub.c:5859 #3: ffff88805a941198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #3: ffff88805a941198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1005 #4: ffff88805894f160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #4: ffff88805894f160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1005 4 locks held by udevd/7005: #0: ffff888053fdd540 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:182 #1: ffff8880203f3488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:154 #2: ffff88805cc63b48 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x75/0x3c0 fs/kernfs/file.c:155 #3: ffff88805a941198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #3: ffff88805a941198 (&dev->mutex){....}-{4:4}, at: uevent_show+0x174/0x330 drivers/base/core.c:2730 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:437 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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: 0 Comm: swapper/1 Not tainted 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 43 cb 12 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: 9907c89b6028cb00 RBX: ffffffff81973d78 RCX: 9907c89b6028cb00 RDX: 0000000000000001 RSI: ffffffff8d748227 RDI: ffffffff8bc1c820 RBP: ffffc90000197f20 R08: ffff8880b8932b5b R09: 1ffff1101712656b R10: dffffc0000000000 R11: ffffed101712656c R12: ffffffff8f7ebf70 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110038dbb40 FS: 0000000000000000(0000) GS:ffff8881261cf000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000c408c89 CR3: 0000000079e4c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x1e8/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147