INFO: task kworker/u4:1:144 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:1    state:D stack:24648 pid:  144 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 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:745
 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:
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c460 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
 #0: ffff888018ffb938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000158fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff8880731560e0 (&type->s_umount_key#52){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff8880776751b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47d/0x660 fs/f2fs/segment.c:528
2 locks held by getty/3954:
 #0: ffff88802bfa4098 (&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+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
5 locks held by syz.0.15/5118:

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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: 5118 Comm: syz.0.15 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5363 [inline]
RIP: 0010:lock_is_held_type+0xaa/0x190 kernel/locking/lockdep.c:5666
Code: 00 00 00 7e 4b 44 89 fd 49 89 df 49 81 c7 f0 0a 00 00 45 31 e4 49 83 fc 31 73 24 4c 89 ff 4c 89 f6 e8 fa 01 00 00 85 c0 75 2a <49> ff c4 48 63 83 e8 0a 00 00 49 83 c7 28 49 39 c4 7c d8 eb 11 48
RSP: 0018:ffffc900031ee5d0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88807ef83b80 RCX: 0000000000000000
RDX: 0000000000000267 RSI: ffff8880b903a318 RDI: ffff88807ef84710
RBP: 00000000ffffffff R08: dffffc0000000000 R09: fffffbfff1ad3196
R10: fffffbfff1ad3196 R11: 1ffffffff1ad3195 R12: 0000000000000004
R13: 0000000000000046 R14: ffff8880b903a318 R15: ffff88807ef84710
FS:  00007f3de9a5b6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f54855db000 CR3: 0000000022c45000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_is_held include/linux/lockdep.h:287 [inline]
 lockdep_assert_rq_held kernel/sched/sched.h:1317 [inline]
 rq_clock_task kernel/sched/sched.h:1477 [inline]
 update_stats_curr_start kernel/sched/fair.c:1054 [inline]
 set_next_entity+0x34a/0x570 kernel/sched/fair.c:4673
 pick_next_task_fair+0x43e/0x850 kernel/sched/fair.c:7581
 __pick_next_task kernel/sched/core.c:5669 [inline]
 pick_next_task kernel/sched/core.c:5777 [inline]
 __schedule+0x82b/0x4390 kernel/sched/core.c:6359
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
RIP: 0010:kmem_cache_alloc+0x144/0x290 mm/slub.c:3238
Code: f8 08 0f 83 99 00 00 00 89 c0 48 0f a3 05 1c 31 ae 0b 73 0d e8 ad 53 a8 ff 84 c0 0f 84 87 00 00 00 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 10 75 7e 48 89 d8 48 83 c4 18 5b 41 5c 41 5d 41 5e 41
RSP: 0018:ffffc900031eea10 EFLAGS: 00000202
RAX: 5cad5dd13819dd00 RBX: ffff888076dac780 RCX: 5cad5dd13819dd00
RDX: 00000000000000c8 RSI: ffffffff8a59a220 RDI: ffffffff8a59a1e0
RBP: 0000000000092800 R08: 0000000000000140 R09: ffff888076dac780
R10: 00000000d9e713e2 R11: 000000003b1dd5f1 R12: ffff88801b865280
R13: ffff888076dac780 R14: ffffffff819e034f R15: ffff88801b865280
 mempool_alloc+0x18f/0x4e0 mm/mempool.c:393
 bio_alloc_bioset+0x124/0x870 block/bio.c:466
 f2fs_grab_read_bio+0xa7/0x730 fs/f2fs/data.c:990
 f2fs_submit_page_read+0xaf/0x2b0 fs/f2fs/data.c:1035
 f2fs_get_read_data_page+0x390/0x560 fs/f2fs/data.c:1224
 gc_data_segment fs/f2fs/gc.c:1504 [inline]
 do_garbage_collect+0x3dfb/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+0x1962/0x3310 fs/f2fs/data.c:1700
 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: 0033:0x7f3dea7d6eb9
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:00007f3de9a5b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3dea972f80 RCX: 00007f3dea7d6eb9
RDX: 00000000200000c0 RSI: 0000000040305828 RDI: 0000000000000004
RBP: 00007f3dea84493e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3dea972f80 R15: 00007ffe8a984b38
 </TASK>