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.1:12314 blocked for more than 140 seconds. Not tainted 4.14.176-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28688 12314 6349 0x00000004 Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x946/0xe40 kernel/time/timer.c:1723 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x160/0x290 kernel/locking/semaphore.c:238 down+0x57/0x80 kernel/locking/semaphore.c:62 console_lock+0x24/0x70 kernel/printk/printk.c:2216 con_shutdown+0x3d/0x90 drivers/tty/vt/vt.c:2941 release_tty+0xb6/0x7a0 drivers/tty/tty_io.c:1501 tty_release_struct+0x37/0x50 drivers/tty/tty_io.c:1616 tty_release+0xaa6/0xd60 drivers/tty/tty_io.c:1776 __fput+0x25f/0x790 fs/file_table.c:210 task_work_run+0x113/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1d6/0x220 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+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x416421 RSP: 002b:00007fff2c27b670 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000416421 RDX: 0000000000000000 RSI: 0000000000000b6d RDI: 0000000000000004 RBP: 0000000000000001 R08: 0000000036c50b6d R09: 0000000036c50b71 R10: 00007fff2c27b750 R11: 0000000000000293 R12: 000000000076c900 R13: 000000000076c900 R14: 00000000000450f8 R15: 000000000076bfac INFO: task syz-executor.5:12381 blocked for more than 140 seconds. Not tainted 4.14.176-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D29728 12381 6350 0x00000004 Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468 chrdev_open+0x1fc/0x540 fs/char_dev.c:423 do_dentry_open+0x732/0xe90 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x8ca/0x3c50 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_sys_open+0x29d/0x3f0 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c889 RSP: 002b:00007f3baa047c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f3baa0486d4 RCX: 000000000045c889 RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000076bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000079a R14: 00000000004ca51c R15: 000000000076bfac Showing all locks held in the system: 1 lock held by khungtaskd/1056: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544 1 lock held by in:imklog/6013: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0xa6/0xc0 fs/file.c:769 1 lock held by syz-executor.1/12314: #0: (tty_mutex){+.+.}, at: [] tty_release_struct+0x2c/0x50 drivers/tty/tty_io.c:1615 1 lock held by syz-executor.5/12381: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1056 Comm: khungtaskd Not tainted 4.14.176-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+0x13e/0x194 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x139/0x17e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e2/0xb80 kernel/hung_task.c:274 kthread+0x30d/0x420 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: 12356 Comm: syz-executor.5 Not tainted 4.14.176-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88803a436440 task.stack: ffff88803deb0000 RIP: 0010:__sanitizer_cov_trace_pc+0x3d/0x50 kernel/kcov.c:87 RSP: 0018:ffff88803deb73c8 EFLAGS: 00000246 RAX: 0000000000040000 RBX: ffff8880000a0050 RCX: ffffc90007863000 RDX: 000000000003ffff RSI: ffffffff831eabd3 RDI: ffff88803deb7480 RBP: 0000000000000050 R08: 000000000000ffff R09: ffffed104325e6a4 R10: ffffed104325e6a3 R11: ffff8882192f351f R12: ffff8880000a0006 R13: 0000000000000000 R14: 00000000e31c872e R15: 000000000000004f FS: 00007f3baa069700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000130e978 CR3: 00000000a1386000 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+0x943/0x1880 drivers/video/fbdev/vga16fb.c:923 bit_clear_margins+0x2a4/0x480 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x285/0x310 drivers/video/fbdev/core/fbcon.c:1320 fbcon_switch+0xcdf/0x1780 drivers/video/fbdev/core/fbcon.c:2302 redraw_screen+0x331/0x770 drivers/tty/vt/vt.c:689 fbcon_modechanged+0x59d/0x890 drivers/video/fbdev/core/fbcon.c:2949 fbcon_event_notify+0x11a/0x1746 drivers/video/fbdev/core/fbcon.c:3302 notifier_call_chain+0x107/0x1a0 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+0x79/0x90 kernel/notifier.c:325 fb_set_var+0xaad/0xc70 drivers/video/fbdev/core/fbmem.c:1054 do_fb_ioctl+0x3cc/0x940 drivers/video/fbdev/core/fbmem.c:1127 fb_ioctl+0xdd/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+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c889 RSP: 002b:00007f3baa068c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3baa0696d4 RCX: 000000000045c889 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000006 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002f0 R14: 00000000004c54e4 R15: 000000000076bf0c Code: a7 a7 7e 81 e2 00 01 1f 00 75 0b 8b 90 50 13 00 00 83 fa 01 74 01 c3 48 8b 34 24 48 8b 88 58 13 00 00 8b 80 54 13 00 00 48 8b 11 <48> 83 c2 01 48 39 d0 76 e2 48 89 34 d1 48 89 11 c3 66 90 41 57