INFO: task syz-executor.0:30315 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.0 D28928 30315 6375 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_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1497
__fput+0x25f/0x7a0 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+0x1ad/0x200 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+0x46/0xbb
RIP: 0033:0x416721
RSP: 002b:00007fff2316fca0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000416721
RDX: 0000001b31b20000 RSI: ffffffff8640008a RDI: 0000000000000003
RBP: 0000000000000001 R08: ffffffff810071c6 R09: 0000000080682160
R10: 00007fff2316fd90 R11: 0000000000000293 R12: 000000000078c900
R13: 000000000078c900 R14: ffffffffffffffff R15: 000000000078bfac
Showing all locks held in the system:
1 lock held by khungtaskd/1057:
#0: (tasklist_lock){.+.?}, at: [<ffffffff8146c8d0>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
1 lock held by in:imklog/5986:
#0: (&f->f_pos_lock){+.+.}, at: [<ffffffff8191e4e6>] __fdget_pos+0xa6/0xc0 fs/file.c:769
1 lock held by syz-executor.0/30315:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff8318192e>] fb_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1497
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 1057 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 30323 Comm: syz-executor.2 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880a87924c0 task.stack: ffff8880a9858000
RIP: 0010:__sanitizer_cov_trace_pc+0x29/0x50 kernel/kcov.c:71
RSP: 0018:ffff8880a985f3d8 EFLAGS: 00000246
RAX: ffff8880a87924c0 RBX: ffff8880000a0050 RCX: ffffc9000af24000
RDX: 0000000000000001 RSI: ffffffff831f9ef3 RDI: ffff8880a985f490
RBP: 0000000000000050 R08: 000000000000ffff R09: ffffed1014bdaf74
R10: ffffed1014bdaf73 R11: ffff8880a5ed7b9f R12: ffff8880000a0032
R13: 0000000000000000 R14: 00000000d37278b1 R15: 000000000000004f
FS: 00007fcf6cad7700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055aec0d999f8 CR3: 000000008454b000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
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+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_event_notify+0x11a/0x1750 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/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: 0033:0x45cba9
RSP: 002b:00007fcf6cad6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e5c80 RCX: 000000000045cba9
RDX: 0000000020000080 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000002fe R14: 00000000004c5931 R15: 00007fcf6cad76d4
Code: ff 90 65 48 8b 04 25 40 ee 01 00 48 85 c0 74 1a 65 8b 15 db 47 a7 7e 81 e2 00 01 1f 00 75 0b 8b 90 58 13 00 00 83 fa 01 74 01 c3 <48> 8b 34 24 48 8b 88 60 13 00 00 8b 80 5c 13 00 00 48 8b 11 48