linux-kernel - [syzbot] [f2fs?] INFO: task hung in process_one

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Message-ID: <6973f686.a70a0220.35de72.0009.GAE@google.com>
Date: Fri, 23 Jan 2026 14:30:30 -0800
From: syzbot <syzbot+5dd7feff22865a110a30@...kaller.appspotmail.com>
To: chao@...nel.org, jaegeuk@...nel.org, 
	linux-f2fs-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [f2fs?] INFO: task hung in process_one_work (5)

Hello,

syzbot found the following issue on:

HEAD commit:    59e4d31a0470 Merge branches 'for-next/core' and 'for-next/..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=12454e3a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8a8594efdc14f07a
dashboard link: https://syzkaller.appspot.com/bug?extid=5dd7feff22865a110a30
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14ba2b9a580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15da1852580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/746a1d5c4188/disk-59e4d31a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2eefade79f10/vmlinux-59e4d31a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/140624ef24ed/Image-59e4d31a.gz.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/d9aeb36c73e1/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=179533fa580000)
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/2795c5404b6f/mount_6.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=11856bfc580000)
mounted in repro #3: https://storage.googleapis.com/syzbot-assets/c5955f1ccd09/mount_11.gz
  fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=10ba2b9a580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5dd7feff22865a110a30@...kaller.appspotmail.com

INFO: task kworker/u8:14:3572 blocked for more than 143 seconds.
Workqueue: writeback wb_workfn (flush-7:1)
 writeback_sb_inodes+0x73c/0x16b4 fs/fs-writeback.c:2030
 __writeback_inodes_wb+0xec/0x228 fs/fs-writeback.c:2107
 wb_writeback+0x3c8/0xd70 fs/fs-writeback.c:2218
 wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
 wb_do_writeback fs/fs-writeback.c:2375 [inline]
 wb_workfn+0xa08/0xdc0 fs/fs-writeback.c:2403
 process_one_work+0x7c0/0x1558 kernel/workqueue.c:3257
      Not tainted syzkaller #0
Call trace:
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write+0xb4/0xc0 kernel/locking/rwsem.c:1591
 process_one_work+0x7c0/0x1558 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3421
 kthread+0x5fc/0x75c kernel/kthread.c:463
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
1 lock held by khungtaskd/32:
4 locks held by kworker/u8:2/41:
4 locks held by kworker/u8:3/42:
2 locks held by pr/ttyAMA-1/43:
 #2: ffff0000d49500e0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x24/0xdc fs/super.c:563
 #2: ffff0000cb9880e0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x24/0xdc fs/super.c:563
4 locks held by kworker/u8:20/6003:
 #3: ffff0000e0531510 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2313 [inline]
 #3: ffff0000e0531510 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x4c0/0x6d8 fs/f2fs/segment.c:464
 #0: ffff0000d535d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #0: ffff0000c1ff2948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x63c/0x1558 kernel/workqueue.c:3231
 #1: ffff80009ee57be0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x6d0/0x1558 kernel/workqueue.c:3231


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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