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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 69e434a1cb21 Linux 6.1.63
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1574cff0e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=8936a912d77a129d
dashboard link: https://syzkaller.appspot.com/bug?extid=14f1764576ca2d1d60ef
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8f4c34d49102/disk-69e434a1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/415c50ae270f/vmlinux-69e434a1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/71f602f135dc/Image-69e434a1.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+14f176...@syzkaller.appspotmail.com

INFO: task syz-fuzzer:4251 blocked for more than 143 seconds.
Not tainted 6.1.63-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-fuzzer state:D stack:0 pid:4251 ppid:4217 flags:0x00000008
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
rwsem_down_write_slowpath+0xc80/0x156c kernel/locking/rwsem.c:1189
__down_write_common kernel/locking/rwsem.c:1314 [inline]
__down_write kernel/locking/rwsem.c:1323 [inline]
down_write+0x84/0x88 kernel/locking/rwsem.c:1574
inode_lock include/linux/fs.h:756 [inline]
vfs_unlink+0xd8/0x508 fs/namei.c:4242
do_unlinkat+0x4c8/0x708 fs/namei.c:4321
__do_sys_unlinkat fs/namei.c:4364 [inline]
__se_sys_unlinkat fs/namei.c:4357 [inline]
__arm64_sys_unlinkat+0xcc/0xfc fs/namei.c:4357
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffff8000159f4df0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
#0: ffff8000159f55f0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
#0: ffff8000159f4c20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:305
2 locks held by syslogd/3829:
3 locks held by klogd/3833:
2 locks held by getty/3982:
#0: ffff0000d5d4b098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
#1: ffff80001bca02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2188
3 locks held by syz-fuzzer/4251:
#0: ffff0000d7a12460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:393
#1: ffff000129312218 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:791 [inline]
#1: ffff000129312218 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x2cc/0x708 fs/namei.c:4304
#2: ffff00012930e850 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#2: ffff00012930e850 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_unlink+0xd8/0x508 fs/namei.c:4242
4 locks held by syz-executor.2/27420:
1 lock held by syz-executor.4/27443:

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



---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

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