INFO: task syz.4.714:7575 blocked for more than 144 seconds.
      Not tainted 5.15.166-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.714       state:D stack:25784 pid: 7575 ppid:  7321 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6515
 rwsem_down_read_slowpath+0x605/0xb40 kernel/locking/rwsem.c:1055
 __down_read_common kernel/locking/rwsem.c:1239 [inline]
 __down_read kernel/locking/rwsem.c:1252 [inline]
 down_read+0x9a/0x2e0 kernel/locking/rwsem.c:1500
 iterate_supers+0xac/0x1e0 fs/super.c:714
 ksys_sync+0xb9/0x1c0 fs/sync.c:102
 __do_sys_sync+0xa/0x10 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f064b1cdef9
RSP: 002b:00007f0649605038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f064b387130 RCX: 00007f064b1cdef9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f064b24001e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f064b387130 R15: 00007ffde349bc38
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91fbe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3327:
 #0: ffff88814b394098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc9000209b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
1 lock held by syz-executor/3558:
3 locks held by kworker/u4:7/3672:
1 lock held by syz-executor/4147:
 #0: ffff888079f080e0 (&type->s_umount_key#54){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
1 lock held by syz-executor/4176:
 #0: ffff88801a9f00e0 (&type->s_umount_key#54){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
1 lock held by syz-executor/4347:
 #0: ffff8880632300e0 (&type->s_umount_key#54){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
1 lock held by syz.4.714/7575:
 #0: ffff88801a9f00e0 (&type->s_umount_key#54){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
1 lock held by udevd/8902:
2 locks held by udevd/8903:

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.166-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8903 Comm: udevd Not tainted 5.15.166-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:arch_atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline]
RIP: 0010:arch_atomic_long_read include/linux/atomic/atomic-long.h:29 [inline]
RIP: 0010:atomic_long_read include/linux/atomic/atomic-instrumented.h:1184 [inline]
RIP: 0010:__mutex_trylock_common+0x99/0x2e0 kernel/locking/mutex.c:101
Code: 54 24 38 4a 89 04 32 65 48 8b 05 42 92 a0 7e 48 89 44 24 18 be 08 00 00 00 e8 e3 46 68 00 4c 89 e0 48 c1 e8 03 42 80 3c 30 00 <74> 08 4c 89 e7 e8 3d 45 68 00 49 8b 1c 24 4d 89 fd 49 c1 ed 03 48
RSP: 0018:ffffc900035d7920 EFLAGS: 00000246
RAX: 1ffff11003732000 RBX: dffffc0000000000 RCX: ffffffff8161dd8d
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88801b990000
RBP: ffffc900035d79f0 R08: dffffc0000000000 R09: ffffed1003732001
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88801b990000
R13: ffff88801b990000 R14: dffffc0000000000 R15: ffffc900035d7980
FS:  00007f60cdd5ec80(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbc6fd28060 CR3: 0000000052ada000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __mutex_trylock kernel/locking/mutex.c:146 [inline]
 __mutex_lock_common+0x1e8/0x25a0 kernel/locking/mutex.c:598
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 ep_send_events fs/eventpoll.c:1686 [inline]
 ep_poll+0x617/0x1e90 fs/eventpoll.c:1856
 do_epoll_wait+0x1ae/0x220 fs/eventpoll.c:2291
 __do_sys_epoll_wait fs/eventpoll.c:2303 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2298 [inline]
 __x64_sys_epoll_wait+0x253/0x2a0 fs/eventpoll.c:2298
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f60cde96457
Code: 73 01 c3 48 8b 0d d1 d9 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 e8 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 76 48 8b 15 a2 d9 0c 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffc33da4018 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f60cde96457
RDX: 0000000000000004 RSI: 00007ffc33da4058 RDI: 0000000000000004
RBP: 00007ffc33da4064 R08: 0000000000000007 R09: b36a725af0d4bfa4
R10: 00000000ffffffff R11: 0000000000000246 R12: 00005622862dee90
R13: 00007ffc33da4058 R14: 0000000000000001 R15: 00005622862b7910
 </TASK>