INFO: task udevd:4408 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:26832 pid:4408 ppid:3641 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6562
schedule+0xb9/0x180 kernel/sched/core.c:6638
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6697
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
device_lock include/linux/device.h:885 [inline]
uevent_show+0x16e/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+0x460/0xc50 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+0x471/0x960 fs/read_write.c:470
ksys_read+0x14d/0x260 fs/read_write.c:613
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff240ca7407
RSP: 002b:00007ffdfadb7d90 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007ff24135d880 RCX: 00007ff240ca7407
RDX: 0000000000001000 RSI: 000056288cf74a00 RDI: 0000000000000008
RBP: 00007ff240defff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007ff240defea0 R14: 0000000000000000 R15: 000056288cfb74b0
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
3 locks held by kworker/u4:2/37:
#0: ffff8880b8f3ad18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538
#1: ffff8880b8f27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x400/0x740 kernel/sched/psi.c:999
#2: ffff8880b8f28458 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
2 locks held by pvrusb2-context/2311:
#0: ffff8880598e0188 (&hdw->big_lock_mutex){+.+.}-{3:3}, at: pvr2_hdw_initialize+0xe1/0x3c10 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2326
#1: ffffffff8c9da690 (umhelper_sem){++++}-{3:3}, at: usermodehelper_read_trylock+0xf9/0x2b0 kernel/umh.c:218
2 locks held by getty/4031:
#0: ffff88802f6dc098 (&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+0x41e/0x1360 drivers/tty/n_tty.c:2198
2 locks held by kworker/1:7/4321:
6 locks held by kworker/0:5/4326:
#0: ffff888142ace938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004477d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffff888145700190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#2: ffff888145700190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5845
#3: ffff8880591b2190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff8880591b2190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0xf8/0x8a0 drivers/usb/core/hub.c:2305
#4: ffff8880268d8118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#4: ffff8880268d8118 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1100 [inline]
#4: ffff8880268d8118 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb1/0x7c0 drivers/base/dd.c:1303
#5: ffff8880598e0188 (&hdw->big_lock_mutex){+.+.}-{3:3}, at: pvr2_hdw_disconnect+0x69/0x4f0 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2710
2 locks held by kworker/u4:7/4349:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900044c7d00 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
4 locks held by udevd/4408:
#0: ffff8880570d59e0 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182
#1: ffff88805728c888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x59/0x410 fs/kernfs/file.c:172
#2: ffff888028b4b660 (kn->active#5){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888028b4b660 (kn->active#5){.+.+}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
#3: ffff8880591b2190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff8880591b2190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16e/0x320 drivers/base/core.c:2669
5 locks held by kworker/0:7/4423:
#0: ffff888142ace938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900047bfd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffff8880281e0190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#2: ffff8880281e0190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5845
#3: ffff88807e55e190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff88807e55e190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1010
#4: ffff88807e55a118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#4: ffff88807e55a118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1010
3 locks held by kworker/0:9/4425:
#0: ffff888142ace938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900047dfd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffff888145718190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#2: ffff888145718190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5845
4 locks held by udevd/4458:
#0: ffff88807debd1c8 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182
#1: ffff88807b3d4888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x59/0x410 fs/kernfs/file.c:172
#2: ffff88807d3f9578 (kn->active#5){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff88807d3f9578 (kn->active#5){.+.+}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
#3: ffff88807e55e190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff88807e55e190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16e/0x320 drivers/base/core.c:2669
2 locks held by kworker/u4:10/4548:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004bbfd00 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 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+0xf0e/0xf50 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: 4546 Comm: kworker/u4:8 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:40 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:75 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:107 [inline]
RIP: 0010:lock_is_held_type+0x68/0x190 kernel/locking/lockdep.c:5701
Code: 48 8b 1d 6b 92 d7 75 83 bb dc 0a 00 00 00 0f 85 df 00 00 00 41 89 f7 49 89 fe 48 c7 04 24 00 00 00 00 9c 8f 04 24 4c 8b 2c 24 48 c7 c7 80 24 8c 8a e8 eb 12 00 00 65 ff 05 b4 9c d7 75 83 bb
RSP: 0018:ffffc90004b6f6c8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff888025a79e00 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 00000000ffffffff RDI: ffff8880b8f3ad18
RBP: 00000000ffffffff R08: 0000000000000001 R09: 1ffff11004b4f61d
R10: dffffc0000000000 R11: ffffed1004b4f3c1 R12: 0000000000000001
R13: 0000000000000046 R14: ffff8880b8f3ad18 R15: 00000000ffffffff
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f98f1fa1fd0 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_is_held include/linux/lockdep.h:283 [inline]
lockdep_assert_rq_held kernel/sched/sched.h:1353 [inline]
psi_group_change+0xe3/0x13b0 kernel/sched/psi.c:789
psi_task_switch+0x400/0x740 kernel/sched/psi.c:999
psi_sched_switch kernel/sched/stats.h:189 [inline]
__schedule+0x1bef/0x4030 kernel/sched/core.c:6557
schedule+0xb9/0x180 kernel/sched/core.c:6638
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
toggle_allocation_gate+0x25c/0x470 mm/kfence/core.c:828
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295