NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
INFO: task syz-executor.4:11122 blocked for more than 140 seconds.
      Not tainted 4.14.166-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28528 11122   7195 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414ee1
RSP: 002b:00007ffc74b3a520 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000414ee1
RDX: 0000001b2d020000 RSI: 00000000000018f7 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00000000159418f7 R09: 00000000159418fb
R10: 00007ffc74b3a600 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 0000000000764030 R15: 000000000075c07c
INFO: task syz-executor.5:11130 blocked for more than 140 seconds.
      Not tainted 4.14.166-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D28528 11130   7193 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414ee1
RSP: 002b:00007ffc88174790 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000414ee1
RDX: 0000000000000000 RSI: 00000000000018f7 RDI: 0000000000000006
RBP: 0000000000000001 R08: 00000000159418f7 R09: 00000000159418fb
R10: 00007ffc88174870 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 0000000000761168 R15: 000000000075bfd4
INFO: task syz-executor.3:11162 blocked for more than 140 seconds.
      Not tainted 4.14.166-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D29488 11162   7192 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468
 chrdev_open+0x207/0x590 fs/char_dev.c:423
 do_dentry_open+0x73b/0xeb0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:891
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1084
 SYSC_openat fs/open.c:1111 [inline]
 SyS_openat+0x30/0x40 fs/open.c:1105
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45b349
RSP: 002b:00007f9afd8c6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9afd8c76d4 RCX: 000000000045b349
RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000772 R14: 00000000004c8dbe R15: 000000000075bfd4
INFO: task syz-executor.2:11152 blocked for more than 140 seconds.
      Not tainted 4.14.166-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D29488 11152   7191 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468
 chrdev_open+0x207/0x590 fs/char_dev.c:423
 do_dentry_open+0x73b/0xeb0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:891
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1084
 SYSC_openat fs/open.c:1111 [inline]
 SyS_openat+0x30/0x40 fs/open.c:1105
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45b349
RSP: 002b:00007f6ca6577c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f6ca65786d4 RCX: 000000000045b349
RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000772 R14: 00000000004c8dbe R15: 000000000075bf2c

Showing all locks held in the system:
1 lock held by khungtaskd/1059:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81489c18>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544
1 lock held by rsyslogd/7024:
 #0:  (&f->f_pos_lock){+.+.}, at: [<ffffffff8196444b>] __fdget_pos+0xab/0xd0 fs/file.c:769
2 locks held by getty/7146:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6643>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca4c6>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7147:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6643>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca4c6>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7148:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6643>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca4c6>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7149:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6643>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca4c6>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7150:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6643>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca4c6>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7151:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6643>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca4c6>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7152:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6643>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca4c6>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.4/11122:
 #0:  (&fb_info->lock){+.+.}, at: [<ffffffff83282a55>] fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
1 lock held by syz-executor.5/11130:
 #0:  (&fb_info->lock){+.+.}, at: [<ffffffff83282a55>] fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
1 lock held by syz-executor.3/11162:
 #0:  (&fb_info->lock){+.+.}, at: [<ffffffff83283397>] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468
1 lock held by syz-executor.2/11152:
 #0:  (&fb_info->lock){+.+.}, at: [<ffffffff83283397>] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468

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

NMI backtrace for cpu 0
CPU: 0 PID: 1059 Comm: khungtaskd Not tainted 4.14.166-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x142/0x197 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x141/0x189 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:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5e7/0xb90 kernel/hung_task.c:274
 kthread+0x319/0x430 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 11145 Comm: syz-executor.3 Not tainted 4.14.166-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880515a2500 task.stack: ffff888048640000
RIP: 0010:__sanitizer_cov_trace_pc+0x41/0x60 kernel/kcov.c:87
RSP: 0018:ffff888048647320 EFLAGS: 00000246
RAX: 0000000000040000 RBX: ffff8880000a0010 RCX: ffffc9000602d000
RDX: 000000000003ffff RSI: ffffffff833013f0 RDI: ffff8880486473f0
RBP: ffff888048647320 R08: 00000000fffffe20 R09: ffffed10432af4d4
R10: ffffed10432af4d3 R11: ffff88821957a69f R12: 0000000000000010
R13: 0000000000000000 R14: 0000000018ac54eb R15: ffff8880000a0000
FS:  00007f9afd8e8700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c431b99110 CR3: 000000008c54e000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 writeb arch/x86/include/asm/io.h:65 [inline]
 vga16fb_fillrect+0x940/0x1880 drivers/video/fbdev/vga16fb.c:923
 bit_clear_margins+0x2d5/0x4f0 drivers/video/fbdev/core/bitblit.c:232
 fbcon_clear_margins+0x292/0x320 drivers/video/fbdev/core/fbcon.c:1317
 fbcon_switch+0xd38/0x1820 drivers/video/fbdev/core/fbcon.c:2299
 redraw_screen+0x335/0x7c0 drivers/tty/vt/vt.c:688
 fbcon_modechanged+0x59e/0x880 drivers/video/fbdev/core/fbcon.c:2946
 fbcon_event_notify+0x11f/0x17af drivers/video/fbdev/core/fbcon.c:3299
 notifier_call_chain+0x111/0x1b0 kernel/notifier.c:93
 __blocking_notifier_call_chain kernel/notifier.c:317 [inline]
 __blocking_notifier_call_chain kernel/notifier.c:304 [inline]
 blocking_notifier_call_chain kernel/notifier.c:328 [inline]
 blocking_notifier_call_chain+0x80/0xa0 kernel/notifier.c:325
 fb_notifier_call_chain+0x25/0x30 drivers/video/fbdev/core/fb_notify.c:45
 fb_set_var+0xb09/0xcf0 drivers/video/fbdev/core/fbmem.c:1054
 do_fb_ioctl+0x3cc/0x940 drivers/video/fbdev/core/fbmem.c:1127
 fb_ioctl+0xe6/0x130 drivers/video/fbdev/core/fbmem.c:1242
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45b349
RSP: 002b:00007f9afd8e7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9afd8e86d4 RCX: 000000000045b349
RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000002cd R14: 00000000004c3dc6 R15: 000000000075bf2c
Code: e2 00 01 1f 00 75 0b 8b 90 50 13 00 00 83 fa 01 74 01 c3 55 48 89 e5 48 8b 75 08 48 8b 88 58 13 00 00 8b 80 54 13 00 00 48 8b 11 <48> 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00