INFO: task kworker/u8:9:6398 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:9 state:D stack:24392 pid:6398 tgid:6398 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:1)
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_balance_fs+0x5ab/0x7f0 fs/f2fs/segment.c:464
f2fs_write_inode+0x3fb/0x5f0 fs/f2fs/inode.c:820
write_inode fs/fs-writeback.c:1564 [inline]
__writeback_single_inode+0x6f1/0xff0 fs/fs-writeback.c:1784
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 khungtaskd/31:
#0: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5607:
#0: ffff8880319080a0 (&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 syz-executor/5851:
#0: ffff88805489e0e0 (&type->s_umount_key#64){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88805489e0e0 (&type->s_umount_key#64){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88805489e0e0 (&type->s_umount_key#64){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
#1: ffffffff8dd42d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff8dd42d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
4 locks held by kworker/u8:9/6398:
#0: ffff88801f2b5148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88801f2b5148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc9000bbc7ba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc9000bbc7ba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff88807f9640e0 (&type->s_umount_key#50){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:562
#3: ffff88802514d478 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2294 [inline]
#3: ffff88802514d478 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5ab/0x7f0 fs/f2fs/segment.c:464
6 locks held by syz.1.310/7201:
2 locks held by kworker/u8:12/7641:
#0: ffff88801e39a948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88801e39a948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc9000c43fba0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc9000c43fba0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
5 locks held by syz.3.874/9820:
#0: ffff8880251a20e0 (&type->s_umount_key#49/1){+.+.}-{4:4}, at: alloc_super+0x1bb/0x930 fs/super.c:344
#1: ffff8880b863a018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:646
#2: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#2: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#2: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: prepend_path+0x4d/0x830 fs/d_path.c:164
#3: ffffffff8da167c8 (rename_lock.seqcount){+.+.}-{0:0}, at: read_seqbegin_or_lock include/linux/seqlock.h:1130 [inline]
#3: ffffffff8da167c8 (rename_lock.seqcount){+.+.}-{0:0}, at: prepend_path+0x22a/0x830 fs/d_path.c:171
#4: ffff88801c2fe528 (&p->pi_lock){-.-.}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline]
#4: ffff88801c2fe528 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0x67/0x12b0 kernel/sched/core.c:4181
=============================================
NMI backtrace for cpu 1
CPU: 1 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7201 Comm: syz.1.310 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:lock_is_held include/linux/lockdep.h:249 [inline]
RIP: 0010:iput+0xd7/0xc50 fs/inode.c:1933
Code: 48 89 6c 24 10 43 0f b6 04 2f 84 c0 0f 85 e3 02 00 00 8b 1d 0b eb 1e 0d 31 ff 89 de e8 62 0c 82 ff 85 db 74 2d 48 8b 7c 24 20 ff ff ff ff e8 3f 69 fc 08 89 c3 bf 01 00 00 00 89 c6 e8 41 0c
RSP: 0018:ffffc9001d216f08 EFLAGS: 00000202
RAX: ffffffff823d9b8e RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff88802a8ddac0 RSI: 0000000000000001 RDI: ffff88805942e340
RBP: ffff88805942e378 R08: ffffea0001f7a7f7 R09: 1ffffd40003ef4fe
R10: dffffc0000000000 R11: fffff940003ef4ff R12: ffff88805942e4a8
R13: dffffc0000000000 R14: ffff88805942e2a8 R15: 1ffffffff1eb90d2
FS: 00007ff93b6a76c0(0000) GS:ffff888126169000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe590eacb8 CR3: 000000003229a000 CR4: 00000000003526f0
Call Trace:
gc_data_segment fs/f2fs/gc.c:-1 [inline]
do_garbage_collect+0x4dab/0x6b60 fs/f2fs/gc.c:1833
f2fs_gc+0xc8d/0x25a0 fs/f2fs/gc.c:1938
f2fs_balance_fs+0x5f7/0x7f0 fs/f2fs/segment.c:466
f2fs_map_blocks+0x3452/0x40d0 fs/f2fs/data.c:1789
f2fs_expand_inode_data+0x62a/0xa70 fs/f2fs/file.c:1931
f2fs_fallocate+0x4f5/0x990 fs/f2fs/file.c:2034
vfs_fallocate+0x669/0x7e0 fs/open.c:342
ksys_fallocate fs/open.c:366 [inline]
__do_sys_fallocate fs/open.c:371 [inline]
__se_sys_fallocate fs/open.c:369 [inline]
__x64_sys_fallocate+0xc0/0x110 fs/open.c:369
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff93a78eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff93b6a7038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007ff93a9e5fa0 RCX: 00007ff93a78eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007ff93a811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008000c62 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff93a9e6038 R14: 00007ff93a9e5fa0 R15: 00007ffca3aded38