INFO: task syz.1.781:8495 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.781 state:D stack:25768 pid:8495 ppid:5768 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747
sync_bdevs+0x1af/0x330 block/bdev.c:1076
ksys_sync+0xc6/0x170 fs/sync.c:105
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6275f9acb9
RSP: 002b:00007f6276e23028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f6276215fa0 RCX: 00007f6275f9acb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f6276215fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6276216038 R14: 00007f6276215fa0 R15: 00007fff0d9e5988
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8d12ffe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8d12ffe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8d12ffe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by getty/5529:
#0: ffff88802d5010a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217
1 lock held by udevd/5772:
#0: ffff8881407564c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
2 locks held by kworker/1:5/5836:
#0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711
#1: ffffc90004bbfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90004bbfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711
3 locks held by kworker/1:6/5853:
#0: ffff888017c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711
#1: ffffc90004bcfd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90004bcfd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711
#2: ffff88805a3f5240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x286/0x31b0 drivers/net/netdevsim/fib.c:1491
1 lock held by syz.1.781/8495:
#0: ffff8881407564c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076
1 lock held by syz-executor/8577:
2 locks held by kworker/u4:14/9501:
#0: ffff888017c71538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017c71538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711
#1: ffffc9000542fd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc9000542fd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711
1 lock held by syz.5.1431/10663:
#0: ffff8881407564c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076
1 lock held by modprobe/11015:
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 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+0x18c/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf3d/0xf80 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9498 Comm: kworker/u4:13 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound idle_cull_fn
RIP: 0010:__bfs kernel/locking/lockdep.c:1737 [inline]
RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1844 [inline]
RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2804 [inline]
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3138 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3253 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3869 [inline]
RIP: 0010:__lock_acquire+0x3319/0x7d40 kernel/locking/lockdep.c:5137
Code: 30 b7 11 ff c0 25 ff 0f 00 00 89 05 51 30 b7 11 48 85 db 0f 84 8c 05 00 00 4c 8d 73 10 4d 89 f5 49 c1 ed 03 41 80 7c 15 00 00 <74> 12 4c 89 f7 e8 9d df 76 00 48 ba 00 00 00 00 00 fc ff df 4c 89
RSP: 0018:ffffc90005367580 EFLAGS: 00000046
RAX: ffffffff93ce3098 RBX: ffffffff93ce3098 RCX: 0000000000000008
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff90b5e040
RBP: ffffc900053677c8 R08: ffffc90005367757 R09: 0000000000000000
R10: ffffc90005367720 R11: fffff52000a6ceeb R12: 1ffffffff21775c9
R13: 1ffffffff279c615 R14: ffffffff93ce30a8 R15: ffff88807d29a9c8
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4c8bdb9fe8 CR3: 000000002cac0000 CR4: 00000000003506e0
Call Trace:
lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162
debug_object_activate+0x6c/0x4f0 lib/debugobjects.c:709
debug_timer_activate kernel/time/timer.c:782 [inline]
__mod_timer+0x88d/0xdb0 kernel/time/timer.c:1119
idle_cull_fn+0x323/0x520 kernel/workqueue.c:2373
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293