INFO: task syz-executor.5:9778 can't die for more than 143 seconds.
task:syz-executor.5  state:D stack:27512 pid: 9778 ppid:  9340 flags:0x00000004
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
 loop_clr_fd drivers/block/loop.c:1237 [inline]
 lo_ioctl+0x398/0x17c0 drivers/block/loop.c:1562
 blkdev_ioctl+0x37a/0x800 block/ioctl.c:609
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f0cda4cf8a7
RSP: 002b:00007f0cd7a44fa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000020000080 RCX: 00007f0cda4cf8a7
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004
RBP: 00007f0cd7a456bc R08: 00007f0cd7a45040 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000005 R14: 00007f0cd7a45000 R15: 00000000200001c0
 </TASK>
INFO: task syz-executor.5:9778 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.5  state:D stack:27512 pid: 9778 ppid:  9340 flags:0x00000004
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
 loop_clr_fd drivers/block/loop.c:1237 [inline]
 lo_ioctl+0x398/0x17c0 drivers/block/loop.c:1562
 blkdev_ioctl+0x37a/0x800 block/ioctl.c:609
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f0cda4cf8a7
RSP: 002b:00007f0cd7a44fa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000020000080 RCX: 00007f0cda4cf8a7
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004
RBP: 00007f0cd7a456bc R08: 00007f0cd7a45040 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000005 R14: 00007f0cd7a45000 R15: 00000000200001c0
 </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/6434:
 #0: ffff88801c08d4f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990
2 locks held by agetty/6442:
 #0: ffff88807f2f1098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252
 #1: ffffc900029282e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113
2 locks held by systemd-udevd/9743:
 #0: ffff88801a11a918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev.part.0+0x9b/0xb50 block/bdev.c:819
 #1: ffff88801a0fe360 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_open+0x75/0x120 drivers/block/loop.c:1733
1 lock held by syz-executor.5/9778:
 #0: ffff88801a0fe360 (&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: 29785 Comm: syz-executor.4 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:put_ucounts+0x7f/0x1c0 kernel/ucount.c:210
Code: 24 58 31 c0 e8 12 90 28 00 48 8d 7d 1c 48 c7 c6 40 50 a5 8b 48 8d 54 24 20 e8 8d 23 ab 02 31 ff 41 89 c4 89 c6 e8 11 92 28 00 <45> 85 e4 0f 84 cb 00 00 00 e8 e3 8f 28 00 48 8d 7d 08 48 89 f8 48
RSP: 0000:ffffc9001914fbd0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 1ffff92003229f7a RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff888146ef3a80 RDI: 0000000000000003
RBP: ffffffff8ba550a0 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff814f140f R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000090 R15: 0000000000000000
FS:  00007fee73764700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fee76195b11 CR3: 000000016104d000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 do_dec_rlimit_put_ucounts+0xe4/0x170 kernel/ucount.c:302
 __sigqueue_free kernel/signal.c:455 [inline]
 __sigqueue_free kernel/signal.c:450 [inline]
 dequeue_synchronous_signal kernel/signal.c:748 [inline]
 get_signal+0x102a/0x28b0 kernel/signal.c:2715
 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207
 irqentry_exit_to_user_mode+0x5/0x40 kernel/entry/common.c:313
 exc_page_fault+0xc6/0x180 arch/x86/mm/fault.c:1544
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:568
RIP: 0033:0x7fee76195452
Code: ff e8 62 33 01 00 85 c0 0f 84 ba 01 00 00 64 f0 83 2c 25 b8 ff ff ff 01 e8 6b d1 00 00 48 8b 0c 24 8b 00 48 8b 99 80 00 00 00 <89> 81 88 00 00 00 85 c0 75 06 48 83 fb ff 74 18 48 63 44 24 14 48
RSP: 002b:00007fee737641a0 EFLAGS: 00010203
RAX: 0000000000000013 RBX: 00000002be5741c3 RCX: 00007fee76195a89
RDX: 00007fee7619542e RSI: 0000000000000001 RDI: 00007fee737645f0
RBP: 00007fee76248f6d R08: 00007fee737641a0 R09: 00007fee76248f6d
R10: 00007ffeb79f3090 R11: 0000000000022f62 R12: 0000000000000000
R13: 00007ffeb79e508f R14: 00007fee73764300 R15: 0000000000022000
 </TASK>
----------------
Code disassembly (best guess):
   0:	24 58                	and    $0x58,%al
   2:	31 c0                	xor    %eax,%eax
   4:	e8 12 90 28 00       	callq  0x28901b
   9:	48 8d 7d 1c          	lea    0x1c(%rbp),%rdi
   d:	48 c7 c6 40 50 a5 8b 	mov    $0xffffffff8ba55040,%rsi
  14:	48 8d 54 24 20       	lea    0x20(%rsp),%rdx
  19:	e8 8d 23 ab 02       	callq  0x2ab23ab
  1e:	31 ff                	xor    %edi,%edi
  20:	41 89 c4             	mov    %eax,%r12d
  23:	89 c6                	mov    %eax,%esi
  25:	e8 11 92 28 00       	callq  0x28923b
* 2a:	45 85 e4             	test   %r12d,%r12d <-- trapping instruction
  2d:	0f 84 cb 00 00 00    	je     0xfe
  33:	e8 e3 8f 28 00       	callq  0x28901b
  38:	48 8d 7d 08          	lea    0x8(%rbp),%rdi
  3c:	48 89 f8             	mov    %rdi,%rax
  3f:	48                   	rex.W