INFO: task kworker/u4:2:150 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:2    state:D stack:21080 pid:  150 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 rwsem_down_write_slowpath+0xc87/0x1260 kernel/locking/rwsem.c:1165
 f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
 f2fs_write_inode+0x531/0x760 fs/f2fs/inode.c:745
 write_inode fs/fs-writeback.c:1505 [inline]
 __writeback_single_inode+0x6c3/0xda0 fs/fs-writeback.c:1715
 writeback_sb_inodes+0xa4e/0x1680 fs/fs-writeback.c:1940
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
 wb_writeback+0x46f/0xbe0 fs/fs-writeback.c:2116
 wb_check_background_flush fs/fs-writeback.c:2182 [inline]
 wb_do_writeback fs/fs-writeback.c:2270 [inline]
 wb_workfn+0xbd6/0xf20 fs/fs-writeback.c:2298
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31eb20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
 #0: ffff888019bf8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000168fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff8880755080e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff8880773451b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by kworker/u4:2/150:
 #0: ffff888019bf8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc900016efd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff88807b0b40e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807aa611b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by kworker/u4:3/895:
 #0: ffff888019bf8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc900042cfd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff888141de40e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff8880798651b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by kworker/u4:4/3034:
 #0: ffff888019bf8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000ce2fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff88807621a0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff888061e051b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by kworker/u4:5/3098:
 #0: ffff888019bf8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000d22fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff888075bd40e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807d1ad1b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
2 locks held by getty/3947:
 #0: ffff88814d0c9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
5 locks held by syz.0.16/5106:
7 locks held by syz.1.17/5128:
4 locks held by syz.2.18/5147:
4 locks held by kworker/u4:7/5159:
 #0: ffff888019bf8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000348fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff888024d000e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff8880536691b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
5 locks held by syz.3.19/5173:
4 locks held by kworker/u4:8/5186:
 #0: ffff888019bf8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000354fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff88805425a0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807d1851b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by syz.4.20/5203:
7 locks held by syz.5.21/5232:
4 locks held by kworker/u4:10/5243:
 #0: ffff888019bf8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc900036efd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff888019baa0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff8880604b11b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by syz.6.22/5266:
5 locks held by syz.7.23/5296:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5128 Comm: syz.1.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:mark_lock+0x10/0x320 kernel/locking/lockdep.c:4552
Code: 4c 89 f7 41 89 d9 e9 79 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53 50 89 d5 49 89 f6 <48> 89 fb 49 bd 00 00 00 00 00 fc ff df 83 fa 08 75 29 4d 8d 7e 20
RSP: 0018:ffffc9000332e5c0 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff88802b6328a8 RCX: ffffffff815dca24
RDX: 0000000000000002 RSI: ffff88802b632950 RDI: ffff88802b631dc0
RBP: 0000000000000002 R08: ffffffff901d5207 R09: 1ffffffff203aa40
R10: dffffc0000000000 R11: fffffbfff203aa41 R12: ffff88802b632970
R13: 0000000000000004 R14: ffff88802b632950 R15: ffff88802b632950
FS:  00007f376769b6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5f7ffd5040 CR3: 0000000023e90000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 mark_held_locks kernel/locking/lockdep.c:4193 [inline]
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4211 [inline]
 lockdep_hardirqs_on_prepare+0x249/0x770 kernel/locking/lockdep.c:4278
 trace_hardirqs_on+0x67/0x80 kernel/trace/trace_preemptirq.c:49
 kasan_quarantine_put+0xd4/0x220 mm/kasan/quarantine.c:231
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 submit_bio_checks+0x316/0x1910 block/blk-core.c:899
 __submit_bio+0x5ca/0x820 block/blk-core.c:911
 __submit_bio_noacct_mq block/blk-core.c:997 [inline]
 submit_bio_noacct+0x6b0/0x800 block/blk-core.c:1027
 submit_bio+0x2c1/0x560 block/blk-core.c:1089
 f2fs_submit_page_read+0x239/0x2b0 fs/f2fs/data.c:1056
 f2fs_get_read_data_page+0x395/0x580 fs/f2fs/data.c:1230
 gc_data_segment fs/f2fs/gc.c:1504 [inline]
 do_garbage_collect+0x3ff7/0x6300 fs/f2fs/gc.c:1671
 f2fs_gc+0x8da/0x1950 fs/f2fs/gc.c:1765
 f2fs_balance_fs+0x492/0x650 fs/f2fs/segment.c:529
 f2fs_map_blocks+0x2972/0x3300 fs/f2fs/data.c:1752
 expand_inode_data+0x4bf/0x700 fs/f2fs/file.c:1717
 f2fs_fallocate+0x423/0x8c0 fs/f2fs/file.c:1819
 vfs_fallocate+0x587/0x6f0 fs/open.c:308
 ioctl_preallocate fs/ioctl.c:294 [inline]
 file_ioctl fs/ioctl.c:334 [inline]
 do_vfs_ioctl+0x1b52/0x1ef0 fs/ioctl.c:853
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl+0x83/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f37684568f9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f376769b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3768684080 RCX: 00007f37684568f9
RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000004
RBP: 00007f37684e9984 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f3768684080 R15: 00007ffc5df5d388
 </TASK>