INFO: task syz-executor.2:6568 blocked for more than 143 seconds.
      Not tainted 5.16.0-rc1-next-20211118-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:23928 pid: 6568 ppid:     1 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4987 [inline]
 __schedule+0xa9a/0x4940 kernel/sched/core.c:6268
 schedule+0xd2/0x260 kernel/sched/core.c:6341
 blk_mq_freeze_queue_wait+0x112/0x160 block/blk-mq.c:178
 __loop_clr_fd+0x1ae/0x1070 drivers/block/loop.c:1122
 lo_release+0x1ac/0x1f0 drivers/block/loop.c:1761
 blkdev_put_whole block/bdev.c:694 [inline]
 blkdev_put+0x2fb/0x9e0 block/bdev.c:956
 deactivate_locked_super+0x94/0x160 fs/super.c:335
 deactivate_super+0xad/0xd0 fs/super.c:366
 cleanup_mnt+0x3a2/0x540 fs/namespace.c:1137
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f969a418f57
RSP: 002b:00007ffe5747f938 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f969a418f57
RDX: 00007ffe5747fa0a RSI: 000000000000000a RDI: 00007ffe5747fa00
RBP: 00007ffe5747fa00 R08: 00000000ffffffff R09: 00007ffe5747f7d0
R10: 0000555557001903 R11: 0000000000000246 R12: 00007f969a471105
R13: 00007ffe57480ac0 R14: 0000555557001810 R15: 00007ffe57480b00
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/26:
 #0: ffffffff8bb83ba0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458
1 lock held by in:imklog/6451:
 #0: ffff8880216eb770 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990
2 locks held by syz-executor.2/6568:
 #0: ffff88801abfc918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x97/0x9e0 block/bdev.c:914
 #1: ffff88801abf8360 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x7a/0x1070 drivers/block/loop.c:1106

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

NMI backtrace for cpu 1
CPU: 1 PID: 26 Comm: khungtaskd Not tainted 5.16.0-rc1-next-20211118-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:254 [inline]
 watchdog+0xcb7/0xed0 kernel/hung_task.c:339
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2968 Comm: systemd-journal Not tainted 5.16.0-rc1-next-20211118-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:entry_SYSCALL_64+0x3/0x15 arch/x86/entry/entry_64.S:92
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 0f 01 f8 <65> 48 89 24 25 14 a0 00 00 65 48 8b 24 25 10 70 02 00 6a 2b 65 ff
RSP: 0018:00007ffeaa9b24c8 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 00007ffeaa9b4f40 RCX: 00007f2608c47210
RDX: 0000000000002000 RSI: 00007ffeaa9b2d40 RDI: 0000000000000009
RBP: 0000000000000000 R08: 0000000000000008 R09: 00007ffeaa9e4080
R10: 00007ffeaa9e40f0 R11: 0000000000000246 R12: 00007ffeaa9b2d40
R13: 00007ffeaa9b4e98 R14: 0000564e1fe19958 R15: 0005d14be173bf7e
FS:  00007f26096b88c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2606bf3000 CR3: 000000007b017000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
----------------
Code disassembly (best guess):
   0:	cc                   	int3
   1:	cc                   	int3
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   5:	cc                   	int3
   6:	cc                   	int3
   7:	cc                   	int3
   8:	cc                   	int3
   9:	cc                   	int3
   a:	cc                   	int3
   b:	cc                   	int3
   c:	cc                   	int3
   d:	cc                   	int3
   e:	cc                   	int3
   f:	cc                   	int3
  10:	cc                   	int3
  11:	cc                   	int3
  12:	cc                   	int3
  13:	cc                   	int3
  14:	cc                   	int3
  15:	cc                   	int3
  16:	cc                   	int3
  17:	cc                   	int3
  18:	cc                   	int3
  19:	cc                   	int3
  1a:	cc                   	int3
  1b:	cc                   	int3
  1c:	cc                   	int3
  1d:	cc                   	int3
  1e:	cc                   	int3
  1f:	cc                   	int3
  20:	cc                   	int3
  21:	cc                   	int3
  22:	cc                   	int3
  23:	cc                   	int3
  24:	cc                   	int3
  25:	cc                   	int3
  26:	cc                   	int3
  27:	0f 01 f8             	swapgs
* 2a:	65 48 89 24 25 14 a0 	mov    %rsp,%gs:0xa014 <-- trapping instruction
  31:	00 00
  33:	65 48 8b 24 25 10 70 	mov    %gs:0x27010,%rsp
  3a:	02 00
  3c:	6a 2b                	pushq  $0x2b
  3e:	65                   	gs
  3f:	ff                   	.byte 0xff