INFO: task kworker/u8:21:15083 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:21 state:D stack:23384 pid:15083 tgid:15083 ppid:2 task_flags:0x4208160 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185
__down_write_common kernel/locking/rwsem.c:1317 [inline]
__down_write kernel/locking/rwsem.c:1326 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591
f2fs_down_write fs/f2fs/f2fs.h:2294 [inline]
f2fs_issue_checkpoint+0x3a8/0x610 fs/f2fs/checkpoint.c:1893
f2fs_balance_fs_bg+0x54d/0x980 fs/f2fs/segment.c:544
f2fs_write_node_pages+0x146/0x6e0 fs/f2fs/node.c:2218
do_writepages+0x32e/0x550 mm/page-writeback.c:2604
__writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1719
writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:2015
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2086
wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2197
wb_check_old_data_flush fs/fs-writeback.c:2301 [inline]
wb_do_writeback fs/fs-writeback.c:2354 [inline]
wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2382
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
6 locks held by kauditd/30:
1 lock held by khungtaskd/31:
#0: ffffffff8e33d320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e33d320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e33d320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5625:
#0: ffff88814d2740a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by kworker/u8:20/15082:
#0: ffff888146a8b948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff888146a8b948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc90004497ba0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc90004497ba0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
4 locks held by kworker/u8:21/15083:
#0: ffff88801eeae948 (
(wq_completion)writeback
){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc90004387ba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc90004387ba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff888087bce0e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:562
#3: ffff8880319bd478 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2294 [inline]
#3: ffff8880319bd478 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x3a8/0x610 fs/f2fs/checkpoint.c:1893
7 locks held by syz.0.3025/20118:
1 lock held by syz-executor/22604:
#0: ffffffff8e342db8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e342db8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
1 lock held by syz.8.3840/23076:
#0: ffffffff8e342c80 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3820
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
vkms_vblank_simulate: vblank timer overrun
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3 Comm: pool_workqueue_ Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:number+0x25d/0xf60 lib/vsprintf.c:469
Code: eb 1b e8 46 a1 44 f6 4c 8b 64 24 40 49 83 fc 01 48 8b 44 24 20 83 d0 ff 48 89 44 24 20 c1 7c 24 3c 10 80 e3 20 48 89 5c 24 28 18 00 00 00 48 8d bc 24 80 00 00 00 31 f6 e8 7f 45 aa f6 41 0f
RSP: 0018:ffffc90000a08200 EFLAGS: 00000046
RAX: ffffffff8b7bb9d3 RBX: 00000005ffff0a00 RCX: ffff88801d2ebc80
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000a08320 R08: ffff88801d2ebc80 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000010000 R12: 0000000000000511
R13: 0000000000000511 R14: ffffc90000a08601 R15: 0000000005ffff0a
FS: 0000000000000000(0000) GS:ffff888125afc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558d2e3608 CR3: 0000000076ea2000 CR4: 00000000003526f0
Call Trace:
vsnprintf+0x91b/0xf00 lib/vsprintf.c:2890
sprintf+0xd9/0x120 lib/vsprintf.c:3089
print_time kernel/printk/printk.c:1354 [inline]
info_print_prefix+0x155/0x310 kernel/printk/printk.c:1380
record_print_text+0x154/0x420 kernel/printk/printk.c:1429
printk_get_next_message+0x26d/0x7b0 kernel/printk/printk.c:2997
console_emit_next_record kernel/printk/printk.c:3065 [inline]
console_flush_all+0x4ca/0xb10 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3298
vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
_printk+0xcf/0x120 kernel/printk/printk.c:2448
vkms_vblank_simulate+0x288/0x2f0 drivers/gpu/drm/vkms/vkms_crtc.c:27
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:preempt_schedule_irq+0xb0/0x150 kernel/sched/core.c:7256
Code: 24 20 f6 44 24 21 02 74 0c 90 0f 0b 48 f7 03 10 00 00 00 74 64 bf 01 00 00 00 e8 1b cf 0f f6 e8 66 46 47 f6 fb bf 01 00 00 00 5b ab ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0018:ffffc90000087a80 EFLAGS: 00000282
RAX: 6b9b84b4deb4fc00 RBX: 0000000000000000 RCX: 6b9b84b4deb4fc00
RDX: 0000000000000000 RSI: ffffffff8db9fb03 RDI: 0000000000000001
RBP: ffffc90000087b20 R08: ffffffff8fc35777 R09: 1ffffffff1f86aee
R10: dffffc0000000000 R11: fffffbfff1f86aef R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000010f50
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lockdep_unregister_key+0x2c5/0x310 kernel/locking/lockdep.c:6616
Code: 65 48 8b 05 5d 1e 24 11 48 3b 44 24 10 0f 84 26 fe ff ff e8 0d 7f e1 09 e8 38 80 e1 09 41 f7 c7 00 02 00 00 74 bd fb 40 84 ed <75> bc eb cd 90 0f 0b 90 e9 19 ff ff ff 90 0f 0b 90 e9 2a ff ff ff
RSP: 0018:ffffc90000087be0 EFLAGS: 00000246
RAX: 6b9b84b4deb4fc00 RBX: ffff8880319f4938 RCX: 6b9b84b4deb4fc00
RDX: ffffffff93860358 RSI: ffffffff8dbb4333 RDI: ffffffff8c03da60
RBP: ffff8880319f4900 R08: 0000000000000000 R09: ffffffff81ab1bd8
R10: dffffc0000000000 R11: fffffbfff1f86aef R12: 0000000000000000
R13: 0000000000001000 R14: 0000000000000000 R15: 0000000000000a07
wq_unregister_lockdep kernel/workqueue.c:4848 [inline]
pwq_release_workfn+0x6d5/0x870 kernel/workqueue.c:5144
kthread_worker_fn+0x507/0xb60 kernel/kthread.c:1010
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245