[v6.1] INFO: task hung in f2fs_balance_fs (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4a61839152cc Linux 6.1.61
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11248f08e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=a1472537c0348d87
dashboard link: https://syzkaller.appspot.com/bug?extid=dfa2b7eab955fa4a19c0
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5f10d3d8a196/disk-4a618391.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a5f64dac603f/vmlinux-4a618391.xz
kernel image: https://storage.googleapis.com/syzbot-assets/172392fd3ea1/bzImage-4a618391.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dfa2b7...@syzkaller.appspotmail.com

INFO: task kworker/u4:5:26515 blocked for more than 143 seconds.
Not tainted 6.1.61-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:5 state:D stack:21208 pid:26515 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5241 [inline]
__schedule+0x142d/0x4550 kernel/sched/core.c:6554
schedule+0xbf/0x180 kernel/sched/core.c:6630
rwsem_down_write_slowpath+0xea1/0x14b0 kernel/locking/rwsem.c:1189
f2fs_down_write fs/f2fs/f2fs.h:2170 [inline]
f2fs_balance_fs+0x4fb/0x6c0 fs/f2fs/segment.c:426
f2fs_write_inode+0x4c3/0x540 fs/f2fs/inode.c:749
write_inode fs/fs-writeback.c:1443 [inline]
__writeback_single_inode+0x67d/0x11e0 fs/fs-writeback.c:1660
writeback_sb_inodes+0xc2b/0x1b20 fs/fs-writeback.c:1886
__writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:1957
wb_writeback+0x4b1/0xe10 fs/fs-writeback.c:2062
wb_check_old_data_flush fs/fs-writeback.c:2162 [inline]
wb_do_writeback fs/fs-writeback.c:2215 [inline]
wb_workfn+0xbec/0x1020 fs/fs-writeback.c:2243
process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
kthread+0x28d/0x320 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8d12a230 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8d12aa30 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
#0: ffffffff8d12a060 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:306 [inline]
#0: ffffffff8d12a060 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]
#0: ffffffff8d12a060 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6493
2 locks held by getty/3301:
#0: ffff88814b536098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc900031262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2188
4 locks held by kworker/u4:5/26515:
#0: ffff8881416e4138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
#1: ffffc9000323fd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
#2: ffff88809f0f20e0 (&type->s_umount_key#76){++++}-{3:3}, at: trylock_super+0x1b/0xf0 fs/super.c:415
#3: ffff888091f45140 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2170 [inline]
#3: ffff888091f45140 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x4fb/0x6c0 fs/f2fs/segment.c:426
2 locks held by syz-executor.0/17092:
3 locks held by syz-executor.0/22272:

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.61-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+0x4e1/0x560 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1b0/0x3f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf88/0xfd0 kernel/hung_task.c:377
kthread+0x28d/0x320 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 18536 Comm: kworker/u4:1 Not tainted 6.1.61-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Workqueue: bat_events batadv_nc_worker
RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:409 [inline]
RIP: 0010:batadv_nc_worker+0x17a/0x610 net/batman-adv/network-coding.c:719
Code: 05 19 f2 04 04 01 48 c7 c7 a0 b3 03 8c be ed 02 00 00 48 c7 c2 e0 b3 03 8c e8 42 6a 10 f7 48 89 e8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 ef e8 1c 8a 87 f7 48 8b 6d 00 48 85 ed 74 51 48 81 c5
RSP: 0018:ffffc90004a0fbf8 EFLAGS: 00000246
RAX: 1ffff1100f04a991 RBX: ffff888017665440 RCX: ffff88807c5b5940
RDX: 0000000000000000 RSI: ffffffff8b3cef20 RDI: ffffffff8b3ceee0
RBP: ffff888078254c88 R08: ffffffff8a5a3b5d R09: fffffbfff2091845
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880974b8c80
R13: 0000000000000191 R14: ffff888017665440 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555795ddefd0 CR3: 00000000292d1000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
kthread+0x28d/0x320 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.