シャットダウン時にシステムが必ず drm_ht_find_item+0x5c でクラッシュする

Issue

• drm_ht_find_item+0x5c でカーネルパニックが発生しました。

[252749.643843] BUG: unable to handle kernel NULL pointer dereference at 00000000000008d0
[252749.643874] IP:[<ffffffffa009b8fc>] drm_ht_find_item+0x5c/0xa0 [drm]
[252749.643910] PGD 0 
[252749.643919] Oops:0000 [#1] SMP 
[252749.643933] Modules linked in: tcp_lp fuse dm_mod twnotify(OE) vmw_vsock_vmci_transport vsock ipt_REJECT xt_multiport xt_conntrack iptable_filter xt_REDIRECT iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack coretemp crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd ppdev vmw_balloon pcspkr sg parport_pc parport shpchp i2c_piix4 vmw_vmci nfsd auth_rpcgss nfs_acl lockd grace sunrpc binfmt_misc ip_tables ext4 mbcache jbd2 sr_mod cdrom sd_mod crc_t10dif crct10dif_generic ata_generic pata_acpi crct10dif_pclmul crct10dif_common crc32c_intel serio_raw vmwgfx drm_kms_helper ttm vmxnet3 drm ata_piix libata vmw_pvscsi i2c_core [last unloaded: splxmod]
[252749.644193] CPU:1 PID:716 Comm: plymouthd Tainted:G           OE  ------------   3.10.0-327.el7.x86_64 #1
[252749.644222] Hardware name:VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 09/21/2015
[252749.644252] task: ffff8807661f4500 ti: ffff8808103b4000 task.ti: ffff8808103b4000
[252749.644274] RIP:0010:[<ffffffffa009b8fc>]  [<ffffffffa009b8fc>] drm_ht_find_item+0x5c/0xa0 [drm]
[252749.644308] RSP:0018:ffff8808103b7c68  EFLAGS:00010203
[252749.644324] RAX:00000000000008d0 RBX: ffff880810a0f968 RCX:0000000000000000
[252749.644345] RDX: ffff8808103b7c78 RSI:0000000053efa683 RDI: ffff880810a0f980
[252749.644365] RBP: ffff8808103b7c68 R08:6000000000000000 R09:3418000000000000
[252749.644386] R10:00014fbe9a0c0000 R11: fffeb041b9e3a683 R12: ffff880810a0f980
[252749.644406] R13:0000000053efa683 R14: ffff88080fe6b8c0 R15: ffff88080dc6d688
[252749.644427] FS:00007fd8a22d0740(0000) GS:ffff88083fc80000(0000) knlGS:0000000000000000
[252749.644450] CS:0010 DS:0000 ES:0000 CR0:0000000080050033
[252749.644467] CR2:00000000000008d0 CR3:00000007cfb60000 CR4: 00000000003407e0
[252749.644540] DR0:0000000000000000 DR1:0000000000000000 DR2:0000000000000000
[252749.644573] DR3:0000000000000000 DR6:00000000fffe0ff0 DR7:0000000000000400
[252749.644594] Stack:
[252749.644601]  ffff8808103b7ca0 ffffffffa010cb2d ffff88080dc40000 000000009b3eef73
[252749.644628]  ffff88080dc40000 ffff880811a93e00 ffff88080ec03f00 ffff8808103b7cb0
[252749.644654]  ffffffffa010d50b ffff8808103b7cf8 ffffffffa01345f0 ffff8808103b7d00
[252749.644680] Call Trace:
[252749.644698]  [<ffffffffa010cb2d>] ttm_ref_object_base_unref+0x4d/0xb0 [ttm]
[252749.644722]  [<ffffffffa010d50b>] ttm_vt_unlock+0x1b/0x20 [ttm]
[252749.644744]  [<ffffffffa01345f0>] vmw_master_set+0xd0/0x1b0 [vmwgfx]
[252749.644773]  [<ffffffffa009819d>] drm_setmaster_ioctl+0x7d/0xe0 [drm]
[252749.644794]  [<ffffffff81285678>] ? security_capable+0x18/0x20
[252749.644818]  [<ffffffffa0093b19>] drm_ioctl+0x159/0x6a0 [drm]
[252749.644840]  [<ffffffffa0098120>] ? drm_master_create+0xa0/0xa0 [drm]
[252749.644862]  [<ffffffff813baf89>] ? vt_ioctl+0x499/0x1200
[252749.644884]  [<ffffffffa00939c0>] ? drm_copy_field+0x70/0x70 [drm]
[252749.644924]  [<ffffffffa0132c09>] vmw_generic_ioctl+0x189/0x290 [vmwgfx]
[252749.644946]  [<ffffffffa0132d45>] vmw_unlocked_ioctl+0x15/0x20 [vmwgfx]
[252749.644968]  [<ffffffff811f1ef5>] do_vfs_ioctl+0x2e5/0x4c0
[252749.644985]  [<ffffffff811f2171>] SyS_ioctl+0xa1/0xc0
[252749.645003]  [<ffffffff81645909>] system_call_fastpath+0x16/0x1b
[252749.645020] Code: c1 e1 39 55 4c 01 c0 48 29 c8 48 89 f1 48 89 e5 48 c1 e1 3f 48 01 c8 b9 40 00 00 00 2a 4f 08 48 d3 e8 48 8b 0f 89 c0 48 8d 04 c1 <48> 8b 08 b8 ea ff ff ff 48 85 c9 74 1c 0f 1f 80 00 00 00 00 48 
[252749.645150] RIP  [<ffffffffa009b8fc>] drm_ht_find_item+0x5c/0xa0 [drm]
[252749.645178]  RSP <ffff8808103b7c68>
[252749.645189] CR2:00000000000008d0