RBP: 00007f51108b4ca0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff0eeda9af R14: 00007f51108b59c0 R15: 000000000078bf0c NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 INFO: task syz-executor.3:9949 blocked for more than 140 seconds. Not tainted 4.14.184-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D26608 9949 6363 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384 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+0x5f0/0x1430 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+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb68/0x2aa0 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_sys_open+0x292/0x3e0 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c1d9 RSP: 002b:00007fcc5b79dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000020880 RCX: 000000000045c1d9 RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000078bfe8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bfac R13: 00007fff89d5bcbf R14: 00007fcc5b79e9c0 R15: 000000000078bfac Showing all locks held in the system: 1 lock held by khungtaskd/1060: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by in:imklog/5929: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0xa6/0xc0 fs/file.c:769 1 lock held by syz-executor.3/9949: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1060 Comm: khungtaskd Not tainted 4.14.184-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+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9943 Comm: syz-executor.3 Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888053cd8640 task.stack: ffff8880532a8000 RIP: 0010:bitfill_aligned drivers/video/fbdev/core/cfbfillrect.c:63 [inline] RIP: 0010:bitfill_aligned+0xb2/0x190 drivers/video/fbdev/core/cfbfillrect.c:35 RSP: 0018:ffff8880532af2d0 EFLAGS: 00000246 RAX: 0000000000000028 RBX: ffff8880000a0000 RCX: ffffc9000a529000 RDX: 0000000000000000 RSI: ffffffff831bff7b RDI: 0000000000000a00 RBP: 0000000000000a00 R08: 0000000000000a00 R09: 0000000000000040 R10: ffffed1014b9660b R11: ffff8880a5cb305f R12: 0000000000000040 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fcc5b7bf700(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f242cbce000 CR3: 00000000974d8000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cfb_fillrect+0x3d5/0x720 drivers/video/fbdev/core/cfbfillrect.c:327 vga16fb_fillrect+0x61e/0x1880 drivers/video/fbdev/vga16fb.c:951 bit_clear_margins+0x2a4/0x480 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x274/0x300 drivers/video/fbdev/core/fbcon.c:1320 fbcon_switch+0xc4e/0x1700 drivers/video/fbdev/core/fbcon.c:2302 redraw_screen+0x332/0x760 drivers/tty/vt/vt.c:689 fbcon_modechanged+0x552/0x800 drivers/video/fbdev/core/fbcon.c:2949 fbcon_set_all_vcs+0x35d/0x420 drivers/video/fbdev/core/fbcon.c:2987 fbcon_event_notify+0x72/0x1750 drivers/video/fbdev/core/fbcon.c:3305 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/0x840 drivers/video/fbdev/core/fbmem.c:1127 fb_ioctl+0xda/0x120 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+0x46/0xbb RIP: 0033:0x45c1d9 RSP: 002b:00007fcc5b7bec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000ce80 RCX: 000000000045c1d9 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000004 RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007fff89d5bcbf R14: 00007fcc5b7bf9c0 R15: 000000000078bf0c Code: c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f e9 78 a6 3e fe e8 73 a6 3e fe 45 85 f6 0f 85 b3 00 00 00 e8 65 a6 3e fe 89 e8 31 d2 41 f7 f4 <83> f8 07 89 c5 41 89 c4 76 49 44 8d 60 f8 41 c1 ec 03 49 83 c4