INFO: task kworker/u4:5:4280 blocked for more than 143 seconds.
      Not tainted 5.15.181-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:5    state:D stack:20896 pid: 4280 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 rwsem_down_write_slowpath+0xc46/0x11f0 kernel/locking/rwsem.c:1165
 f2fs_balance_fs+0x47d/0x660 fs/f2fs/segment.c:528
 f2fs_write_inode+0x531/0x760 fs/f2fs/inode.c:738
 write_inode fs/fs-writeback.c:1495 [inline]
 __writeback_single_inode+0x6c3/0xda0 fs/fs-writeback.c:1705
 writeback_sb_inodes+0x9fe/0x1610 fs/fs-writeback.c:1930
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2001
 wb_writeback+0x455/0xb90 fs/fs-writeback.c:2106
 wb_check_background_flush fs/fs-writeback.c:2172 [inline]
 wb_do_writeback fs/fs-writeback.c:2260 [inline]
 wb_workfn+0xb47/0xe60 fs/fs-writeback.c:2288
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 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:
2 locks held by kworker/0:0/7:
1 lock held by khungtaskd/27:
 #0: ffffffff8c11be60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:2/154:
 #0: ffff888019bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000125fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff888148d160e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807b4e11b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47d/0x660 fs/f2fs/segment.c:528
4 locks held by kworker/u4:3/456:
 #0: ffff888019bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900031dfd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88802967e0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807a1ed1b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47d/0x660 fs/f2fs/segment.c:528
4 locks held by kworker/u4:4/1239:
 #0: ffff888019bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90004d57d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff888028b9a0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff8880783091b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47d/0x660 fs/f2fs/segment.c:528
2 locks held by getty/3927:
 #0: ffff88807e628098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025c62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
4 locks held by kworker/u4:5/4280:
 #0: ffff888019bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002eafd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff8880210d40e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88805f5711b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47d/0x660 fs/f2fs/segment.c:528
6 locks held by syz.0.16/5010:
6 locks held by syz.1.17/5031:
4 locks held by kworker/u4:6/5046:
 #0: ffff888019bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000346fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88802a87c0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807b7ed1b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47d/0x660 fs/f2fs/segment.c:528
5 locks held by syz.2.18/5052:
4 locks held by kworker/u4:7/5067:
 #0: ffff888019bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000353fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff8880751280e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff888027dad1b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47d/0x660 fs/f2fs/segment.c:528
5 locks held by syz.3.19/5073:
4 locks held by syz.4.20/5100:
4 locks held by kworker/u4:9/5110:
 #0: ffff888019bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900036bfd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88807d97e0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88807dab11b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47d/0x660 fs/f2fs/segment.c:528
5 locks held by syz.5.21/5128:
5 locks held by syz.6.22/5161:
3 locks held by kworker/u4:12/5184:
1 lock held by udevd/5185:
 #0: ffff88802005d918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
2 locks held by syz.7.23/5187:
 #0: ffff88802005d918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
 #1: ffff88802027a468 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_release+0x4d/0x1f0 drivers/block/loop.c:2071

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.181-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5128 Comm: syz.5.21 Not tainted 5.15.181-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:205
Code: 84 00 00 00 00 00 53 48 89 fb e8 17 00 00 00 48 8b 3d 10 ef f0 0b 48 89 de 5b e9 87 a9 44 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d a4 b1 8a 7e 65 8b 15 a5 b1 8a 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc9000373ed50 EFLAGS: 00000246
RAX: ffffffff8378e0de RBX: ffffea000146d980 RCX: ffff8880197c0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffff9400028db31
R10: fffff9400028db31 R11: 1ffffd400028db30 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffea000146d948 R15: 00fff00000000011
FS:  00007fafd901c6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffea78fafc8 CR3: 00000000223e8000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 _compound_head include/linux/page-flags.h:198 [inline]
 put_page include/linux/mm.h:1233 [inline]
 f2fs_put_page+0x16e/0x380 fs/f2fs/f2fs.h:2601
 f2fs_get_lock_data_page+0x211/0x250 fs/f2fs/data.c:1282
 move_data_page fs/f2fs/gc.c:1336 [inline]
 gc_data_segment fs/f2fs/gc.c:1547 [inline]
 do_garbage_collect+0x3031/0x60a0 fs/f2fs/gc.c:1671
 f2fs_gc+0x8a9/0x1900 fs/f2fs/gc.c:1765
 f2fs_balance_fs+0x491/0x660 fs/f2fs/segment.c:529
 f2fs_map_blocks+0x2976/0x3310 fs/f2fs/data.c:1746
 expand_inode_data+0x4a0/0x6e0 fs/f2fs/file.c:1716
 f2fs_fallocate+0x423/0x8c0 fs/f2fs/file.c:1818
 vfs_fallocate+0x587/0x6f0 fs/open.c:308
 ioctl_preallocate fs/ioctl.c:294 [inline]
 file_ioctl fs/ioctl.c:-1 [inline]
 do_vfs_ioctl+0x1b70/0x1de0 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: 0033:0x7fafd9dcd169
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:00007fafd901c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fafd9ff5080 RCX: 00007fafd9dcd169
RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000004
RBP: 00007fafd9e4fa68 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fafd9ff5080 R15: 00007fff89a1f318
 </TASK>