syzbot

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WARNING: CPU: 2 PID: 5687 at drivers/gpu/drm/drm_modeset_lock.c:97 drm_modeset_lock_all+0x1fa/0x2d0 drivers/gpu/drm/drm_modeset_lock.c:97
Kernel panic - not syncing: panic_on_warn set ...

CPU: 2 PID: 5687 Comm: syz-executor0 Not tainted 4.14.0-rc7-next-20171102+ #9
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 panic+0x1e4/0x41c kernel/panic.c:183
 __warn+0x1c4/0x1e0 kernel/panic.c:546
 report_bug+0x211/0x2d0 lib/bug.c:183
 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:177
 do_trap_no_signal arch/x86/kernel/traps.c:211 [inline]
 do_trap+0x260/0x390 arch/x86/kernel/traps.c:260
 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:297
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:310
 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
RIP: 0010:drm_modeset_lock_all+0x1fa/0x2d0 drivers/gpu/drm/drm_modeset_lock.c:97
RSP: 0018:ffff88002e03f8d8 EFLAGS: 00010212
RAX: 0000000000010000 RBX: ffffffff85656640 RCX: ffffffff829de69a
RDX: 000000000000cd6c RSI: ffffc90000ec2000 RDI: 0000000000000286
RBP: ffff88002e03f8f0 R08: 0000000000000003 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88003c2d88c0 R14: ffff88002e03f9e8 R15: ffff88003c2d88c0
 dpms_legacy drivers/gpu/drm/drm_fb_helper.c:615 [inline]
 drm_fb_helper_dpms.isra.13+0x122/0x4c0 drivers/gpu/drm/drm_fb_helper.c:649
 drm_fb_helper_blank+0x16e/0x1c0 drivers/gpu/drm/drm_fb_helper.c:682
 fb_blank+0x148/0x1f0 drivers/video/fbdev/core/fbmem.c:1072
 do_fb_ioctl+0x72c/0xc80 drivers/video/fbdev/core/fbmem.c:1211
 fb_ioctl+0xdd/0x120 drivers/video/fbdev/core/fbmem.c:1235
 vfs_ioctl fs/ioctl.c:45 [inline]
 do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685
 SYSC_ioctl fs/ioctl.c:700 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x447c89
RSP: 002b:00007f6b038a5bd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6b038a66cc RCX: 0000000000447c89
RDX: 0000000020fb5000 RSI: 0000000000004611 RDI: 0000000000000013
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004a96f0
R13: 0000000000000000 R14: 00007f6b038a59c8 R15: 00007f6b038a5b38
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..