https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_6327/fi-bdw-samus/igt@gem_exec_fence@basic-busy-default.html

<7> [43.483122] [drm:vgem_gem_dumb_create [vgem]] Created object of size 1
<1> [43.483130] BUG: kernel NULL pointer dereference, address: 0000000000000000
<1> [43.483144] #PF: supervisor instruction fetch in kernel mode
<1> [43.483154] #PF: error_code(0x0010) - not-present page
<6> [43.483162] PGD 0 P4D 0 
<4> [43.483170] Oops: 0010 [#1] PREEMPT SMP PTI
<4> [43.483179] CPU: 0 PID: 1007 Comm: gem_exec_fence Tainted: G     U            5.2.0-rc5-CI-CI_DRM_6327+ #1
<4> [43.483192] Hardware name: GOOGLE Samus/Samus, BIOS MrChromebox 08/27/2018
<4> [43.483204] RIP: 0010:0x0
<4> [43.483213] Code: Bad RIP value.
<4> [43.483220] RSP: 0018:ffffc900003a3cf8 EFLAGS: 00010246
<4> [43.483229] RAX: 0000000000000000 RBX: ffff8884655d9548 RCX: 0000000000000000
<4> [43.483240] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8884655d9548
<4> [43.483251] RBP: ffff88846540d698 R08: 0000000000000000 R09: ffff88845ee835a0
<4> [43.483262] R10: 0000000000000000 R11: ffff8884655db050 R12: ffff888466440258
<4> [43.483272] R13: ffffc900003a3dc0 R14: ffffc900003a3dc0 R15: ffffffffa01681f8
<4> [43.483284] FS:  00007f4e1d90be40(0000) GS:ffff88846ea00000(0000) knlGS:0000000000000000
<4> [43.483296] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4> [43.483305] CR2: ffffffffffffffd6 CR3: 000000045b552003 CR4: 00000000003606f0
<4> [43.483315] Call Trace:
<4> [43.483324]  vgem_fence_attach_ioctl+0x64/0x310 [vgem]
<4> [43.483335]  ? __vgem_fence_idr_fini+0x30/0x30 [vgem]
<4> [43.483347]  drm_ioctl_kernel+0x83/0xf0
<4> [43.483357]  drm_ioctl+0x2f3/0x3b0
<4> [43.483366]  ? __vgem_fence_idr_fini+0x30/0x30 [vgem]
<4> [43.483378]  ? get_task_pid+0x150/0x150
<4> [43.483388]  ? _raw_spin_unlock_irqrestore+0x39/0x60
<4> [43.483401]  ? debug_check_no_obj_freed+0x132/0x210
<4> [43.483412]  do_vfs_ioctl+0xa0/0x6e0
<4> [43.483421]  ? lock_acquire+0xa6/0x1c0
<4> [43.483430]  ? get_task_pid+0x150/0x150
<4> [43.483440]  ksys_ioctl+0x35/0x60
<4> [43.483449]  __x64_sys_ioctl+0x11/0x20
<4> [43.483458]  do_syscall_64+0x55/0x1c0
<4> [43.483467]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4> [43.483477] RIP: 0033:0x7f4e1cda35d7
<4> [43.483485] Code: b3 66 90 48 8b 05 b1 48 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 48 2d 00 f7 d8 64 89 01 48
<4> [43.483511] RSP: 002b:00007ffd06372908 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
<4> [43.483523] RAX: ffffffffffffffda RBX: 00007ffd063729f4 RCX: 00007f4e1cda35d7
<4> [43.483535] RDX: 00007ffd06372950 RSI: 00000000c0106441 RDI: 0000000000000007
<4> [43.483546] RBP: 00007ffd06372950 R08: 0000000000000000 R09: 000000000000003c
<4> [43.483557] R10: 0000000000000056 R11: 0000000000000246 R12: 00000000c0106441
<4> [43.483567] R13: 0000000000000007 R14: 0000000000000001 R15: 0000000000000000
<4> [43.483583] Modules linked in: vgem snd_hda_codec_hdmi i915 ax88179_178a usbnet mii x86_pkg_temp_thermal coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel btusb btrtl btbcm btintel snd_hda_intel snd_hda_codec bluetooth snd_hwdep snd_hda_core snd_pcm prime_numbers ecdh_generic mei_me ecc mei lpc_ich