[v5.15] INFO: task hung in deactivate_super

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1fe619a7d252 Linux 5.15.113
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12e85365280000
kernel config: https://syzkaller.appspot.com/x/.config?x=8f10ee30ae29b021
dashboard link: https://syzkaller.appspot.com/bug?extid=906f296f4af9381c2650
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1b707a1e1816/disk-1fe619a7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/19cc598a8bbe/vmlinux-1fe619a7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a6cf7269bae5/Image-1fe619a7.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+906f29...@syzkaller.appspotmail.com

INFO: task syz-executor.0:4002 blocked for more than 143 seconds.
Not tainted 5.15.113-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0 state:D stack: 0 pid: 4002 ppid: 1 flags:0x00000009
Call trace:
__switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
context_switch kernel/sched/core.c:5026 [inline]
__schedule+0xf10/0x1e38 kernel/sched/core.c:6372
schedule+0x11c/0x1c8 kernel/sched/core.c:6455
rwsem_down_write_slowpath+0xca8/0x1340 kernel/locking/rwsem.c:1157
__down_write_common kernel/locking/rwsem.c:1284 [inline]
__down_write kernel/locking/rwsem.c:1293 [inline]
down_write+0x25c/0x260 kernel/locking/rwsem.c:1542
deactivate_super+0x100/0x128 fs/super.c:365
cleanup_mnt+0x3c0/0x474 fs/namespace.c:1143
__cleanup_mnt+0x20/0x30 fs/namespace.c:1150
task_work_run+0x130/0x1e4 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
do_notify_resume+0x262c/0x32b8 arch/arm64/kernel/signal.c:946
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:597
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffff800014ab19a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:268
2 locks held by getty/3727:
#0: ffff0000d1a2f098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
#1: ffff80001a15e2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1200 drivers/tty/n_tty.c:2147
1 lock held by syz-executor.0/4002:
#0: ffff0001209a60e0 (&type->s_umount_key#74){++++}-{3:3}, at: deactivate_super+0x100/0x128 fs/super.c:365
5 locks held by syz-executor.5/4300:
1 lock held by syz-executor.5/4367:
#0: ffff0001209a60e0 (&type->s_umount_key#74){++++}-{3:3}, at: iterate_supers+0xb0/0x1dc fs/super.c:703

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



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[syzbot]

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