INFO: task syz.3.642:6596 blocked for more than 144 seconds.
      Not tainted 5.15.167-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.642       state:D stack:25752 pid: 6596 ppid:  3580 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: 0033:0x7efdc5934ff9
RSP: 002b:00007efdc3dad038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007efdc5aecf80 RCX: 00007efdc5934ff9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007efdc59a7296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007efdc5aecf80 R15: 00007ffd08854c58
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:0/7:
 #0: ffff88814279b138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90000cc7d20 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff88802436d220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #2: ffff88802436d220 (&dev->mutex){....}-{3:3}, at: hub_event+0x208/0x54c0 drivers/usb/core/hub.c:5769
1 lock held by khungtaskd/27:
 #0: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by udevd/3027:
 #0: ffff888020b66118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x14d/0xa50 block/bdev.c:817
2 locks held by getty/3325:
 #0: ffff88814b096098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc9000208e2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
2 locks held by kworker/0:6/3721:
 #0: ffff888017072138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90003fe7d20 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
3 locks held by kworker/0:13/3729:
 #0: ffff888017070938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90003427d20 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8c924228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #2: ffffffff8c924228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x280/0x740 kernel/rcu/tree_exp.h:845
1 lock held by syz.0.556/6101:
 #0: ffff888067e700e0 (&type->s_umount_key#98/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
1 lock held by syz.3.642/6596:
 #0: ffff888067e700e0 (&type->s_umount_key#99){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
1 lock held by syz.3.741/7102:
 #0: ffff888067e700e0 (&type->s_umount_key#99){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
1 lock held by syz-executor/7738:
 #0: ffffffff8c924228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #0: ffffffff8c924228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x350/0x740 kernel/rcu/tree_exp.h:845
2 locks held by syz.4.983/8455:
2 locks held by syz.3.986/8451:
 #0: ffff888020b66118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfb/0x790 block/bdev.c:912
 #1: ffff888020b5c468 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_release+0x4d/0x1f0 drivers/block/loop.c:2070

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3009 Comm: syslogd Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:jhash2 include/linux/jhash.h:129 [inline]
RIP: 0010:hash_stack lib/stackdepot.c:180 [inline]
RIP: 0010:stack_depot_save+0x71/0x440 lib/stackdepot.c:272
Code: 8d 3c f5 7b 71 f5 75 41 83 f8 04 72 73 44 89 ff 44 89 f8 4c 89 e6 03 06 03 7e 04 44 03 7e 08 44 89 fd c1 c5 04 44 29 f8 31 c5 <41> 01 ff 29 ef 89 eb c1 c3 06 31 fb 44 01 fd 89 d9 c1 c1 08 41 29
RSP: 0018:ffffc900024f7ac0 EFLAGS: 00000086
RAX: 00000000cb4fc1d1 RBX: 0000000021e457c6 RCX: 00000000a60f0d23
RDX: 0000000000000800 RSI: ffffc900024f7b44 RDI: 00000000a0e0215b
RBP: 00000000950fe5f5 R08: 0000000000000009 R09: fffffbfff1bd2c16
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc900024f7b20
R13: 1ffff9200049efb8 R14: 0000000000000009 R15: 0000000045e40242
FS:  00007f61ade30380(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056486f279000 CR3: 0000000028dee000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 kasan_save_stack+0x4d/0x60 mm/kasan/common.c:40
 kasan_record_aux_stack+0xba/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3007 [inline]
 call_rcu+0x1c4/0xa70 kernel/rcu/tree.c:3087
 task_work_run+0x129/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f61adf850a8
Code: 48 8b 05 83 9d 0d 00 64 c7 00 16 00 00 00 83 c8 ff 48 83 c4 20 5b c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 5b 48 8b 15 51 9d 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffdb83bec68 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000055ae0cac2910 RCX: 00007f61adf850a8
RDX: 000055ae0cac2c50 RSI: 00007f61ae12330a RDI: 0000000000000003
RBP: 00007ffdb83bed70 R08: 0000000000000001 R09: 0000000000000000
R10: 00007f61ae1233a3 R11: 0000000000000246 R12: 000055ae0cac2c50
R13: 0000000066f893a0 R14: 0000000000000007 R15: 000055ae0cac2a60
 </TASK>