System panics at drm_dp_aux_dev_get_by_minor()

Issue

• Customer has advised issue started with kernel-3.10.0-957.10.1.el7.x86_64

[ 2039.326652] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
[ 2039.337003] IP: [<ffffffffc0a589bd>] drm_dp_aux_dev_get_by_minor+0x3d/0xa0 [drm_kms_helper]
[ 2039.347570] PGD 0 
[ 2039.358024] Oops: 0000 [#1] SMP 
[ 2039.368522] Modules linked in: nvidia_drm(POE) nvidia_modeset(POE) nvidia(POE) drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ipmi_devintf vfio_iommu_type1 vfio nfsv3 nfs fscache nf_log_ipv4 nf_log_common xt_LOG xt_limit ipt_REJECT nf_reject_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack iptable_filter mptctl mptbase ib_isert iscsi_target_mod ib_srpt target_core_mod ib_srp scsi_transport_srp scsi_tgt rpcrdma ib_ucm rdma_ucm ib_uverbs ib_iser ib_umad rdma_cm ib_ipoib iw_cm libiscsi scsi_transport_iscsi ib_cm mlx5_ib ib_core iTCO_wdt iTCO_vendor_support vfat fat sb_edac intel_powerclamp coretemp intel_rapl iosf_mbi kvm_intel kvm irqbypass crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd pcspkr i2c_i801 sg lpc_ich hpwdt hpilo ioatdma
[ 2039.443351]  ipmi_si ipmi_msghandler acpi_power_meter dm_multipath nfsd nfs_acl lockd grace binfmt_misc auth_rpcgss sunrpc ip_tables xfs libcrc32c sd_mod crc_t10dif crct10dif_generic i2c_algo_bit crct10dif_pclmul crct10dif_common crc32c_intel ttm drm tg3 drm_panel_orientation_quirks ixgbe mlx5_core mdio dca hpsa scsi_transport_sas mlxfw devlink wmi ptp pps_core dm_mirror dm_region_hash dm_log dm_mod [last unloaded: ipmi_devintf]
[ 2039.502116] CPU: 1 PID: 9863 Comm: ipmitool Kdump: loaded Tainted: P           OE  ------------   3.10.0-957.12.1.el7.x86_64 #1
[ 2039.533757] Hardware name: HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 10/17/2018
[ 2039.549963] task: ffff89d1bdf11040 ti: ffff89cedd7f0000 task.ti: ffff89cedd7f0000
[ 2039.566430] RIP: 0010:[<ffffffffc0a589bd>]  [<ffffffffc0a589bd>] drm_dp_aux_dev_get_by_minor+0x3d/0xa0 [drm_kms_helper]
[ 2039.583697] RSP: 0018:ffff89cedd7f3bf0  EFLAGS: 00010246
[ 2039.600546] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff89cedd7f3fd8
[ 2039.617670] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffc0a613e0
[ 2039.635612] RBP: ffff89cedd7f3bf8 R08: ffff89f1bcbabbd0 R09: 0000000000000000
[ 2039.653702] R10: ffff89f1be7a1cc0 R11: 0000000000000000 R12: 0000000000000000
[ 2039.671390] R13: ffff89f1b32a2830 R14: ffff89d18fadfa00 R15: 0000000000000000
[ 2039.688297] FS:  00002b45efcc8580(0000) GS:ffff89d1bfc40000(0000) knlGS:0000000000000000
[ 2039.705580] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2039.722916] CR2: 0000000000000018 CR3: 0000001fa372c000 CR4: 00000000001607e0
[ 2039.740399] Call Trace:
[ 2039.757805]  [<ffffffffc0a58a3b>] auxdev_open+0x1b/0x40 [drm_kms_helper]
[ 2039.775708]  [<ffffffffb0846df5>] chrdev_open+0xb5/0x1b0
[ 2039.793514]  [<ffffffffb083ee8a>] do_dentry_open+0x1aa/0x2e0
[ 2039.811151]  [<ffffffffb08f9212>] ? security_inode_permission+0x22/0x30
[ 2039.829061]  [<ffffffffb0846d40>] ? cdev_put+0x30/0x30
[ 2039.846887]  [<ffffffffb083f05a>] vfs_open+0x5a/0xb0
[ 2039.864663]  [<ffffffffb084d568>] ? may_open+0x68/0x120
[ 2039.882483]  [<ffffffffb084fb6d>] do_last+0x1ed/0x12a0
[ 2039.900109]  [<ffffffffb0852a27>] path_openat+0xd7/0x640
[ 2039.917663]  [<ffffffffb085442d>] do_filp_open+0x4d/0xb0
[ 2039.935058]  [<ffffffffb0861ab7>] ? __alloc_fd+0x47/0x170
[ 2039.952303]  [<ffffffffb0840557>] do_sys_open+0x137/0x240
[ 2039.969224]  [<ffffffffb084067e>] SyS_open+0x1e/0x20
[ 2039.985968]  [<ffffffffb0d75d9b>] system_call_fastpath+0x22/0x27
[ 2040.002902] Code: c0 e8 c8 e6 30 f0 48 8b 05 41 8a 00 00 48 85 c0 74 08 89 da 30 d2 3b 10 74 44 89 de 48 c7 c7 e0 13 a6 c0 e8 f6 e7 f1 ef 48 89 c3 <8b> 53 18 85 d2 74 3a 8d 4a 01 48 8d 73 18 89 d0 f0 0f b1 4b 18 
[ 2040.037898] RIP  [<ffffffffc0a589bd>] drm_dp_aux_dev_get_by_minor+0x3d/0xa0 [drm_kms_helper]
[ 2040.055860]  RSP <ffff89cedd7f3bf0>
[ 2040.073914] CR2: 0000000000000018