syzbot

INFO: task syz-executor180:5300 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor180 state:D stack:23880 pid:5300  tgid:5300  ppid:5298   task_flags:0x400140 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:148
 __flush_work+0x9b9/0xbc0 kernel/workqueue.c:4244
 flush_work kernel/workqueue.c:4265 [inline]
 flush_delayed_work+0x13e/0x190 kernel/workqueue.c:4287
 invalidate_dquots fs/quota/dquot.c:576 [inline]
 dquot_disable+0x762/0x1bc0 fs/quota/dquot.c:2296
 ocfs2_disable_quotas+0xfa/0x220 fs/ocfs2/super.c:967
 ocfs2_dismount_volume+0x1b2/0x8d0 fs/ocfs2/super.c:1815
 generic_shutdown_super+0x132/0x2c0 fs/super.c:642
 kill_block_super+0x44/0x90 fs/super.c:1710
 deactivate_locked_super+0xb9/0x130 fs/super.c:473
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1435
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x9a/0x120 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe8f9471ba7
RSP: 002b:00007fff9772f9a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fe8f9471ba7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff9772fa60
RBP: 00007fff9772fa60 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000202 R12: 00007fff97730b10
R13: 000055558cf317c0 R14: 431bde82d7b634db R15: 00007fff97730ab4
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
3 locks held by kworker/u4:9/1095:
2 locks held by getty/5098:
 #0: ffff88801d7a10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000018e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by syz-executor180/5300:
 #0: ffff8880422500e0 (&type->s_umount_key#42){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880422500e0 (&type->s_umount_key#42){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff8880422500e0 (&type->s_umount_key#42){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
3 locks held by syz-executor180/7300:
3 locks held by syz-executor180/7306:
2 locks held by syz-executor180/7309:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 27 Comm: khungtaskd Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:437
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>