INFO: task syz-executor.2:15900 blocked for more than 143 seconds.
      Not tainted 5.5.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D26736 15900   9419 0x80004002
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4081
 schedule+0xdc/0x2b0 kernel/sched/core.c:4155
 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871
 __down_common kernel/locking/semaphore.c:220 [inline]
 __down+0x176/0x2c0 kernel/locking/semaphore.c:237
 down+0x64/0x90 kernel/locking/semaphore.c:61
 console_lock+0x29/0x80 kernel/printk/printk.c:2289
 con_shutdown+0x41/0x90 drivers/tty/vt/vt.c:3277
 release_tty+0xd3/0x470 drivers/tty/tty_io.c:1514
 tty_release_struct+0x3c/0x50 drivers/tty/tty_io.c:1629
 tty_release+0xbcb/0xe90 drivers/tty/tty_io.c:1789
 __fput+0x2ff/0x890 fs/file_table.c:280
 ____fput+0x16/0x20 fs/file_table.c:313
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xba9/0x2f50 kernel/exit.c:801
 do_group_exit+0x135/0x360 kernel/exit.c:899
 get_signal+0x47c/0x24f0 kernel/signal.c:2734
 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815
 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45af49
Code: e8 3c 1f 00 00 eb aa cc cc cc cc cc cc cc cc cc cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 76 40 48 83 ec 28 48 89 6c 24 20 48 <8d> 6c 24 20 48 8b 42 10 48 8b 4a 18 48 8b 52 08 48 89 14 24 48 89
RSP: 002b:00007fb31db2dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: 000000000000017a RBX: 0000000000000005 RCX: 000000000045af49
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000049b96b00
RBP: 000000000075bf20 R08: 0000000020000300 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb31db2e6d4
R13: 00000000004c1701 R14: 00000000004d6660 R15: 00000000ffffffff
INFO: task syz-executor.0:15939 blocked for more than 143 seconds.
      Not tainted 5.5.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D28552 15939   9414 0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4081
 schedule+0xdc/0x2b0 kernel/sched/core.c:4155
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118
 tty_open_by_driver drivers/tty/tty_io.c:1951 [inline]
 tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035
 chrdev_open+0x245/0x6b0 fs/char_dev.c:414
 do_dentry_open+0x4e6/0x1380 fs/open.c:797
 vfs_open+0xa0/0xd0 fs/open.c:914
 do_last fs/namei.c:3420 [inline]
 path_openat+0x10df/0x4500 fs/namei.c:3537
 do_filp_open+0x1a1/0x280 fs/namei.c:3567
 do_sys_open+0x3fe/0x5d0 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1110
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x414ce1
Code: 8b 44 24 24 44 8b 44 24 20 48 8b 5c 24 18 48 8b 54 24 70 48 8b b4 24 90 00 00 00 48 8b bc 24 98 00 00 00 4c 8b 8c 24 88 00 00 <00> 4c 8b 54 24 48 e9 45 ff ff ff 48 89 4c 24 50 44 89 44 24 34 48
RSP: 002b:00007fadf21627a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000414ce1
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007fadf21627d0
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 000000000000000e
R10: 0000000000000064 R11: 0000000000000293 R12: 00007fadf21636d4
R13: 00000000004cc243 R14: 00000000004e6fb0 R15: 00000000ffffffff

Showing all locks held in the system:
1 lock held by khungtaskd/1123:
 #0: ffffffff899a5340 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334
1 lock held by rsyslogd/9281:
 #0: ffff88809b84bde0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801
2 locks held by getty/9371:
 #0: ffff8880a66c9090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc9000193b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/9372:
 #0: ffff8880a8624090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc900019ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/9373:
 #0: ffff888098656090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc9000199b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/9374:
 #0: ffff888095ddc090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc9000196b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/9375:
 #0: ffff8880980ec090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc900019cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/9376:
 #0: ffff88809a7bd090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc9000194b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/9377:
 #0: ffff88808dc18090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc9000190b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.2/15900:
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_release_struct+0x31/0x50 drivers/tty/tty_io.c:1628
1 lock held by syz-executor.0/15939:
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline]
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035
2 locks held by syz-executor.3/15937:
1 lock held by syz-executor.4/15949:
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline]
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035
1 lock held by syz-executor.5/15950:
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline]
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035
1 lock held by syz-executor.1/15974:
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline]
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035
1 lock held by syz-executor.2/15994:
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline]
 #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035

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

NMI backtrace for cpu 1
CPU: 1 PID: 1123 Comm: khungtaskd Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline]
 watchdog+0xb11/0x10c0 kernel/hung_task.c:289
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 15937 Comm: syz-executor.3 Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:180
Code: cc cc cc cc cc cc cc cc cc 65 48 8b 04 25 c0 1e 02 00 48 8b 80 98 13 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 55 <48> 89 e5 65 48 8b 04 25 c0 1e 02 00 65 8b 15 84 f7 8c 7e 81 e2 00
RSP: 0018:ffffc90001a572c8 EFLAGS: 00000206
RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff83c1643f
RDX: 0000000000001400 RSI: 0000000000000000 RDI: 0000000000000005
RBP: ffffc90001a57318 R08: ffff8880a8884100 R09: 0000000000000040
R10: ffffed1014791c4b R11: ffff8880a3c8e25f R12: 0000000000001400
R13: 0000000000000040 R14: ffff8880000a0000 R15: 0000000000000000
FS:  00007f75c7512700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00005bc80 CR3: 00000000a0b7a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 cfb_fillrect+0x423/0x7c0 drivers/video/fbdev/core/cfbfillrect.c:327
 vga16fb_fillrect+0x6ce/0x19b0 drivers/video/fbdev/vga16fb.c:951
 bit_clear_margins+0x30b/0x530 drivers/video/fbdev/core/bitblit.c:232
 fbcon_clear_margins+0x1e9/0x250 drivers/video/fbdev/core/fbcon.c:1372
 fbcon_switch+0xd7f/0x17f0 drivers/video/fbdev/core/fbcon.c:2354
 redraw_screen+0x2b6/0x7d0 drivers/tty/vt/vt.c:997
 fbcon_modechanged+0x5c3/0x790 drivers/video/fbdev/core/fbcon.c:2991
 fbcon_update_vcs+0x42/0x50 drivers/video/fbdev/core/fbcon.c:3038
 fb_set_var+0xb32/0xdd0 drivers/video/fbdev/core/fbmem.c:1051
 do_fb_ioctl+0x390/0x7d0 drivers/video/fbdev/core/fbmem.c:1104
 fb_ioctl+0xe6/0x130 drivers/video/fbdev/core/fbmem.c:1180
 vfs_ioctl fs/ioctl.c:47 [inline]
 file_ioctl fs/ioctl.c:545 [inline]
 do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749
 __do_sys_ioctl fs/ioctl.c:756 [inline]
 __se_sys_ioctl fs/ioctl.c:754 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45af49
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f75c7511c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045af49
RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f75c75126d4
R13: 00000000004c3903 R14: 00000000004d9f18 R15: 00000000ffffffff