syzbot

INFO: task kworker/u4:4:1188 blocked for more than 143 seconds.
      Not tainted 5.15.138-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:4    state:D stack:19520 pid: 1188 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6372
 schedule+0x11b/0x1f0 kernel/sched/core.c:6455
 rwsem_down_write_slowpath+0xebb/0x15c0 kernel/locking/rwsem.c:1157
 __down_write_common kernel/locking/rwsem.c:1284 [inline]
 __down_write kernel/locking/rwsem.c:1293 [inline]
 down_write+0x164/0x170 kernel/locking/rwsem.c:1542
 f2fs_balance_fs+0x4d4/0x6a0 fs/f2fs/segment.c:529
 f2fs_write_inode+0x4c3/0x540 fs/f2fs/inode.c:727
 write_inode fs/fs-writeback.c:1478 [inline]
 __writeback_single_inode+0x644/0xe30 fs/fs-writeback.c:1688
 writeback_sb_inodes+0xbce/0x1a40 fs/fs-writeback.c:1913
 __writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:1984
 wb_writeback+0x465/0xc50 fs/fs-writeback.c:2089
 wb_check_background_flush fs/fs-writeback.c:2155 [inline]
 wb_do_writeback fs/fs-writeback.c:2243 [inline]
 wb_workfn+0xd07/0x1130 fs/fs-writeback.c:2271
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91f020 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:4/1188:
 #0: ffff8881431ce938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc900054a7d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff888078e600e0 (&type->s_umount_key#43){.+.+}-{3:3}, at: trylock_super+0x1b/0xf0 fs/super.c:418
 #3: ffff888078561108 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x4d4/0x6a0 fs/f2fs/segment.c:529
2 locks held by getty/3261:
 #0: ffff888023c7f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900020a32e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
4 locks held by syz-executor154/3523:

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.138-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3523 Comm: syz-executor154 Not tainted 5.15.138-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
RIP: 0010:separate_irq_context kernel/locking/lockdep.c:4526 [inline]
RIP: 0010:__lock_acquire+0xda4/0x1ff0 kernel/locking/lockdep.c:4995
Code: 89 d8 48 c1 e8 03 80 3c 38 00 74 12 48 89 df e8 12 48 67 00 48 bf 00 00 00 00 00 fc ff df 4c 89 3b 48 8b 44 24 40 0f b6 04 38 <84> c0 0f 85 54 0b 00 00 41 8b 5d 00 48 85 db 48 8b 0c 24 74 56 83
RSP: 0018:ffffc9000231ee00 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff8880729c8b90 RCX: ffffffff81628f9f
RDX: 0000000000000000 RSI: 0000000000000008 RDI: dffffc0000000000
RBP: ffff8880729c8ae0 R08: dffffc0000000000 R09: fffffbfff1f79c3a
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000004
R13: ffff8880729c8ae8 R14: 1ffff1100e53915c R15: 4d5ea02f98a35e77
FS:  0000555555de2380(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffde4497338 CR3: 000000001ab22000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622
 down_read+0x45/0x2e0 kernel/locking/rwsem.c:1488
 check_valid_map fs/f2fs/gc.c:881 [inline]
 gc_data_segment fs/f2fs/gc.c:1450 [inline]
 do_garbage_collect+0x20d8/0x7600 fs/f2fs/gc.c:1670
 f2fs_gc+0x9e5/0x1ad0 fs/f2fs/gc.c:1764
 f2fs_balance_fs+0x4e8/0x6a0 fs/f2fs/segment.c:530
 f2fs_map_blocks+0x1989/0x28d0 fs/f2fs/data.c:1672
 expand_inode_data+0x5ba/0x9d0 fs/f2fs/file.c:1697
 f2fs_fallocate+0x35a/0x820 fs/f2fs/file.c:1787
 vfs_fallocate+0x54a/0x6b0 fs/open.c:308
 ksys_fallocate fs/open.c:331 [inline]
 __do_sys_fallocate fs/open.c:339 [inline]
 __se_sys_fallocate fs/open.c:337 [inline]
 __x64_sys_fallocate+0xb9/0x100 fs/open.c:337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f467b501b59
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdcde3ecd8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f467b501b59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f467b57a5f0 R08: 0000555555de34c0 R09: 0000555555de34c0
R10: 0000000008800000 R11: 0000000000000246 R12: 00007ffdcde3ed00
R13: 00007ffdcde3ef28 R14: 431bde82d7b634db R15: 00007f467b54a03b
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.452 msecs