INFO: task agetty:6132 blocked for more than 143 seconds.
      Not tainted 5.15.0-rc4-next-20211007-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:agetty          state:D stack:26968 pid: 6132 ppid:     1 flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4953 [inline]
 __schedule+0x940/0x26f0 kernel/sched/core.c:6234
 schedule+0xd2/0x260 kernel/sched/core.c:6307
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6366
 __mutex_lock_common kernel/locking/mutex.c:672 [inline]
 __mutex_lock+0xa32/0x12f0 kernel/locking/mutex.c:732
 tiocsti drivers/tty/tty_io.c:2308 [inline]
 tty_ioctl+0x89f/0x1670 drivers/tty/tty_io.c:2719
 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: 0033:0x7f189460e017
RSP: 002b:00007ffd3c005fb8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffd3c006139 RCX: 00007f189460e017
RDX: 00007ffd3c006138 RSI: 0000000000005412 RDI: 0000000000000000
RBP: 00007ffd3c006240 R08: ffffffffffffff98 R09: 00007ffd3c006030
R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffd3c005fd4
R13: 00007ffd3c006130 R14: 00007ffd3c006030 R15: 0000000000000000
 </TASK>
INFO: task syz-executor.4:13917 can't die for more than 143 seconds.
task:syz-executor.4  state:R  running task     stack:26744 pid:13917 ppid:  8740 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4953 [inline]
 __schedule+0x940/0x26f0 kernel/sched/core.c:6234
 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6400
 __cond_resched+0x13/0x20 kernel/sched/core.c:8113
 _cond_resched include/linux/sched.h:2026 [inline]
 console_conditional_schedule+0x3c/0x50 kernel/printk/printk.c:2756
 fbcon_redraw.constprop.0+0x33e/0x4b0 drivers/video/fbdev/core/fbcon.c:1673
 fbcon_scroll+0x1d7a/0x3580 drivers/video/fbdev/core/fbcon.c:1782
 con_scroll+0x5b9/0x6d0 drivers/tty/vt/vt.c:630
 lf+0x26b/0x2c0 drivers/tty/vt/vt.c:1507
 vc_con_write_normal drivers/tty/vt/vt.c:2851 [inline]
 do_con_write+0xf1c/0x1e40 drivers/tty/vt/vt.c:2955
 con_put_char+0x70/0xa0 drivers/tty/vt/vt.c:3303
 tty_put_char+0xb7/0x150 drivers/tty/tty_io.c:3173
 do_output_char+0x155/0x850 drivers/tty/n_tty.c:485
 __process_echoes+0x38e/0x9f0 drivers/tty/n_tty.c:736
 flush_echoes drivers/tty/n_tty.c:826 [inline]
 __receive_buf drivers/tty/n_tty.c:1579 [inline]
 n_tty_receive_buf_common+0x1699/0x4780 drivers/tty/n_tty.c:1674
 tty_ldisc_receive_buf+0xa3/0x190 drivers/tty/tty_buffer.c:471
 paste_selection+0x1de/0x4c0 drivers/tty/vt/selection.c:408
 tioclinux+0x126/0x560 drivers/tty/vt/vt.c:3204
 vt_ioctl+0x229a/0x2b10 drivers/tty/vt/vt_ioctl.c:762
 tty_ioctl+0xbbd/0x1670 drivers/tty/tty_io.c:2805
 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: 0033:0x7fdef70a98d9
RSP: 002b:00007fdef4620188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fdef71adf60 RCX: 00007fdef70a98d9
RDX: 0000000020000100 RSI: 000000000000541c RDI: 0000000000000005
RBP: 00007fdef7103cb4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff84de3e1f R14: 00007fdef4620300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:0/8:
1 lock held by khungtaskd/27:
 #0: ffffffff8bb813a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458
1 lock held by in:imklog/6232:
 #0: ffff88802125c370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990
2 locks held by agetty/6132:
 #0: ffff88802b72e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252
 #1: ffff888010c790b8 (&buf->lock){+.+.}-{3:3}, at: tiocsti drivers/tty/tty_io.c:2308 [inline]
 #1: ffff888010c790b8 (&buf->lock){+.+.}-{3:3}, at: tty_ioctl+0x89f/0x1670 drivers/tty/tty_io.c:2719
6 locks held by syz-executor.4/13917:

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.0-rc4-next-20211007-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:105
 nmi_trigger_cpumask_backtrace+0x1ae/0x220 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8 Comm: kworker/u4:0 Not tainted 5.15.0-rc4-next-20211007-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
RIP: 0010:instrument_atomic_read include/linux/instrumented.h:71 [inline]
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:199 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4725 [inline]
RIP: 0010:__lock_acquire+0x6d4/0x54a0 kernel/locking/lockdep.c:4977
Code: c6 48 8d 7b 20 48 89 fa 48 c1 ea 03 42 0f b6 14 3a 84 d2 74 09 80 fa 03 0f 8e 10 2b 00 00 0f b7 53 20 66 81 e2 ff 1f 0f b7 da <be> 08 00 00 00 48 89 d8 48 c1 f8 06 48 8d 3c c5 40 d9 f3 8f e8 13
RSP: 0018:ffffc90000cd7a60 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 00000000000006b6 RCX: 0000000000000001
RDX: 00000000000006b6 RSI: 0000000000000002 RDI: ffff88801198e188
RBP: 0000000000000004 R08: dffffc0000000000 R09: ffffffff8ff3d947
R10: fffffbfff1fe7b28 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88801198d700 R14: ffff88801198e168 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6d9fa89000 CR3: 000000000b88e000 CR4: 00000000003526e0
Call Trace:
 <TASK>
 lock_acquire kernel/locking/lockdep.c:5637 [inline]
 lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602
 rcu_lock_acquire include/linux/rcupdate.h:268 [inline]
 rcu_read_lock include/linux/rcupdate.h:694 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:410 [inline]
 batadv_nc_worker+0x12d/0xfa0 net/batman-adv/network-coding.c:721
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2297
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	48 8d 7b 20          	lea    0x20(%rbx),%rdi
   4:	48 89 fa             	mov    %rdi,%rdx
   7:	48 c1 ea 03          	shr    $0x3,%rdx
   b:	42 0f b6 14 3a       	movzbl (%rdx,%r15,1),%edx
  10:	84 d2                	test   %dl,%dl
  12:	74 09                	je     0x1d
  14:	80 fa 03             	cmp    $0x3,%dl
  17:	0f 8e 10 2b 00 00    	jle    0x2b2d
  1d:	0f b7 53 20          	movzwl 0x20(%rbx),%edx
  21:	66 81 e2 ff 1f       	and    $0x1fff,%dx
  26:	0f b7 da             	movzwl %dx,%ebx
* 29:	be 08 00 00 00       	mov    $0x8,%esi <-- trapping instruction
  2e:	48 89 d8             	mov    %rbx,%rax
  31:	48 c1 f8 06          	sar    $0x6,%rax
  35:	48 8d 3c c5 40 d9 f3 	lea    -0x700c26c0(,%rax,8),%rdi
  3c:	8f
  3d:	e8                   	.byte 0xe8
  3e:	13                   	.byte 0x13