INFO: task syz.1.126:4930 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.126 state:D stack:26496 pid:4930 ppid:4277 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 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
sync_bdevs+0x1ab/0x320 block/bdev.c:1071
ksys_sync+0xb6/0x150 fs/sync.c:105
__ia32_sys_sync+0xa/0x10 fs/sync.c:113
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: 0033:0x7fcdf718f749
RSP: 002b:00007fcdf7fbe038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fcdf73e6180 RCX: 00007fcdf718f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fcdf73e6180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcdf73e6218 R14: 00007fcdf73e6180 R15: 00007ffc60b2c088
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8c92bab0 (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: ffffffff8c92c2d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
3 locks held by kworker/0:1/14:
1 lock held by khungtaskd/28:
#0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by kworker/u4:5/1115:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc9000511fd00 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
2 locks held by getty/4026:
#0: ffff88814caa1098 (&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
2 locks held by syz-executor/4273:
2 locks held by kworker/0:7/4345:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90004a6fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
2 locks held by kworker/u4:6/4348:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90004a9fd00 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/u4:7/4392:
#0: ffff8880b8e3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:545
#1: ffff8880b8e27848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999
#2: ffff8880b8e28418 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x6bf/0xd00 kernel/time/timer.c:1112
2 locks held by kworker/u4:8/4436:
2 locks held by kworker/0:9/4572:
1 lock held by udevd/4768:
#0: ffff888024cd24c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
1 lock held by syz.1.126/4930:
#0: ffff888024cd24c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1ab/0x320 block/bdev.c:1071
6 locks held by kworker/1:8/4934:
#0: ffff88801deeb138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc9000dad7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffff88802808d190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline]
#2: ffff88802808d190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1a7/0x54e0 drivers/usb/core/hub.c:5845
#3: ffff888144b904f8 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3200 [inline]
#3: ffff888144b904f8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5413 [inline]
#3: ffff888144b904f8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
#3: ffff888144b904f8 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5817 [inline]
#3: ffff888144b904f8 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x3068/0x54e0 drivers/usb/core/hub.c:5899
#4: ffff8880278c2f68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5414 [inline]
#4: ffff8880278c2f68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
#4: ffff8880278c2f68 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5817 [inline]
#4: ffff8880278c2f68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x309f/0x54e0 drivers/usb/core/hub.c:5899
#5: ffffffff8d474770 (ehci_cf_port_reset_rwsem){.+.+}-{3:3}, at: hub_port_reset+0x14f/0x1930 drivers/usb/core/hub.c:3057
2 locks held by kworker/0:15/5179:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc9001cf5fd00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
2 locks held by kworker/0:16/5180:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc9001cfcfd00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
2 locks held by dhcpcd/7419:
#0: ffff888071fe1a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
#0: ffff888071fe1a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline]
#0: ffff888071fe1a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1400
#1: ffffffff8c930df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#1: ffffffff8c930df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4345 Comm: kworker/0:7 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events pwq_unbound_release_workfn
RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:5990 [inline]
RIP: 0010:zap_class+0x36d/0x830 kernel/locking/lockdep.c:6036
Code: 48 89 d8 48 c1 e8 06 4c 8b 64 24 08 49 8d 3c c4 be 08 00 00 00 e8 03 f7 6c 00 49 0f ab 1c 24 48 ff 05 d7 6b 2c 11 48 8b 1c 24 <49> 83 c7 08 4c 89 f8 48 c1 e8 03 42 80 3c 30 00 74 08 4c 89 ff e8
RSP: 0018:ffffc90004a6fac8 EFLAGS: 00000046
RAX: 0000000000031ccd RBX: 0000000000000ef7 RCX: 0000000000031cc7
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8f873a98
RBP: 000000000006399a R08: dffffc0000000000 R09: fffffbfff210f4e5
R10: fffffbfff210f4e5 R11: 1ffffffff210f4e4 R12: 0000000000031ccd
R13: 1ffffffff2146ab0 R14: dffffc0000000000 R15: ffffffff90a35580
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c74b3d7660 CR3: 000000001aeca000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__lockdep_free_key_range kernel/locking/lockdep.c:6162 [inline]
lockdep_unregister_key+0x38f/0x530 kernel/locking/lockdep.c:6364
wq_unregister_lockdep kernel/workqueue.c:3500 [inline]
pwq_unbound_release_workfn+0x262/0x2b0 kernel/workqueue.c:3738
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
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