INFO: task kworker/u8:13:3813 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:13 state:D stack:20888 pid:3813 tgid:3813 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x1498/0x5140 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7245
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244
f2fs_down_write fs/f2fs/f2fs.h:2313 [inline]
f2fs_balance_fs+0x5d8/0x800 fs/f2fs/segment.c:464
f2fs_write_inode+0x3fb/0x5f0 fs/f2fs/inode.c:826
write_inode fs/fs-writeback.c:1582 [inline]
__writeback_single_inode+0x7e4/0x1230 fs/fs-writeback.c:1802
writeback_sb_inodes+0x92e/0x1910 fs/fs-writeback.c:2030
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2107
wb_writeback+0x459/0xad0 fs/fs-writeback.c:2218
wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
wb_do_writeback fs/fs-writeback.c:2375 [inline]
wb_workfn+0xaf3/0xf00 fs/fs-writeback.c:2403
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:13/3813:
#0: ffff88801aad7138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88801aad7138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc9000e8c7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc9000e8c7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffff8880381dc0d0 (&type->s_umount_key#55){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff888034c59a80 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2313 [inline]
#3: ffff888034c59a80 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5d8/0x800 fs/f2fs/segment.c:464
2 locks held by getty/5557:
#0: ffff88814d5750a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
6 locks held by syz.0.21/6640:
4 locks held by syz.1.140/7631:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf90/0xfe0 kernel/hung_task.c:515
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7631 Comm: syz.1.140 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:rcu_read_lock_sched include/linux/rcupdate.h:959 [inline]
RIP: 0010:pfn_valid+0xf3/0x480 include/linux/mmzone.h:2184
Code: 00 45 31 c0 45 31 c9 53 e8 ea fb 6f ff 48 83 c4 08 e8 c1 a0 de 08 89 c5 31 ff 89 c6 e8 06 58 94 ff 85 ed 74 1a e8 2d 73 79 ff <84> c0 74 7d e8 44 53 94 ff 4d 85 ff 75 11 e8 3a 53 94 ff eb 3d e8
RSP: 0018:ffffc9000d517398 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff822ee3ba RCX: 0000000080000002
RDX: 0000000000000000 RSI: ffffffff8b85e960 RDI: ffffffff8b85e920
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100785ffe8 R12: dffffc0000000000
R13: dffffc0000000000 R14: 0000000000012297 R15: ffff88813fffa780
FS: 00007f054fd7e6c0(0000) GS:ffff8881266c9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0548d1b000 CR3: 0000000059ee8000 CR4: 00000000003526f0
Call Trace:
page_table_check_clear+0x21/0x5f0 mm/page_table_check.c:70
ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline]
zap_present_ptes mm/memory.c:1685 [inline]
do_zap_pte_range mm/memory.c:1814 [inline]
zap_pte_range mm/memory.c:1858 [inline]
zap_pmd_range mm/memory.c:1950 [inline]
zap_pud_range mm/memory.c:1978 [inline]
zap_p4d_range mm/memory.c:1999 [inline]
unmap_page_range+0x2ee9/0x3cd0 mm/memory.c:2020
unmap_single_vma mm/memory.c:2062 [inline]
unmap_vmas+0x3c0/0x5c0 mm/memory.c:2104
vms_clear_ptes+0x37b/0x570 mm/vma.c:1271
vms_complete_munmap_vmas+0x205/0x890 mm/vma.c:1320
do_vmi_align_munmap+0x3bd/0x4d0 mm/vma.c:1579
do_vmi_munmap+0x252/0x2d0 mm/vma.c:1627
__vm_munmap+0x22c/0x3d0 mm/vma.c:3247
__do_sys_munmap mm/mmap.c:1077 [inline]
__se_sys_munmap mm/mmap.c:1074 [inline]
__x64_sys_munmap+0x60/0x70 mm/mmap.c:1074
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f055071ad27
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f054fd7de08 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 00000000013bd7ef RCX: 00007f055071ad27
RDX: 00000000013bd7ef RSI: 0000000008400000 RDI: 00007f054795e000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007f054fd7dee0 R14: 00007f054fd7dea0 R15: 00007f054795e000