RHEL7: panic in shmem_free_inode

Issue

• panic at shmem_free_inode+0x13

[ 4494.411128] VFS: Busy inodes after unmount of tmpfs. Self-destruct in 5 seconds.  Have a nice day...
[ 4494.411498] BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
[ 4494.420336] IP: [<ffffffff81180f13>] shmem_free_inode+0x13/0x40
[ 4494.427008] PGD 0
[ 4494.429281] Oops: 0000 [#1] SMP
[ 4494.432934] Modules linked in: vhost_net vhost macvtap macvlan xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack 8021q garp mrp nf_conntrack ipt_REJECT tun ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter binfmt_misc bridge stp llc xprtrdma ib_isert iscsi_target_mod ib_iser libiscsi scsi_transport_iscsi ib_srpt target_core_mod ib_srp scsi_transport_srp scsi_tgt ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr iTCO_wdt iTCO_vendor_support mxm_wmi intel_powerclamp coretemp intel_rapl kvm_intel kvm crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd dm_mod pcspkr ses enclosure sb_edac ipmi_ssif edac_core sg mei_me
[ 4494.513138]  mei lpc_ich shpchp mfd_core ipmi_si ipmi_msghandler wmi acpi_pad acpi_power_meter nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables ext4 mbcache jbd2 raid1 sd_mod crc_t10dif crct10dif_generic mgag200 syscopyarea sysfillrect sysimgblt crct10dif_pclmul crct10dif_common i2c_algo_bit crc32c_intel drm_kms_helper ttm ahci drm libahci libata i2c_core enic megaraid_sas
[ 4494.549860] CPU: 10 PID: 1984 Comm: libvirtd Not tainted 3.10.0-327.18.2.el7.x86_64 #1
[ 4494.558757] Hardware name: Cisco Systems Inc UCSC-C240-M4SX/UCSC-C240-M4SX, BIOS C240M4.2.0.10c.0.032320160820 03/23/2016
[ 4494.571068] task: ffff885f6a23b980 ti: ffff885f695e4000 task.ti: ffff885f695e4000
[ 4494.579476] RIP: 0010:[<ffffffff81180f13>]  [<ffffffff81180f13>] shmem_free_inode+0x13/0x40
[ 4494.588879] RSP: 0018:ffff885f695e7d18  EFLAGS: 00010246
[ 4494.594849] RAX: ffff882f73e83970 RBX: 0000000000000000 RCX: 0000000000000034
[ 4494.602869] RDX: 0000000000001ebd RSI: e000000000000000 RDI: ffff885f73568000
[ 4494.610885] RBP: ffff885f695e7d28 R08: 8038000000000000 R09: 2f73e838c01c0000
[ 4494.618909] R10: d06e23a439f23007 R11: ffffffff813b6150 R12: ffff882f73e83808
[ 4494.626926] R13: ffff882f73e83808 R14: ffff882f73e83820 R15: ffff885f7388ba60
[ 4494.634945] FS:  00007fcbe78f5880(0000) GS:ffff882fbff40000(0000) knlGS:0000000000000000
[ 4494.645771] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4494.653961] CR2: 0000000000000030 CR3: 0000005f697f7000 CR4: 00000000001427e0
[ 4494.663703] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 4494.673431] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 4494.683132] Stack:
[ 4494.687064]  ffff882f73e83808 ffff882f73e83808 ffff885f695e7d58 ffffffff81184faf
[ 4494.697153]  ffff882f73e83820 ffff882f73e83928 ffffffff81676d20 ffffffff81676d20
[ 4494.707178]  ffff885f695e7d80 ffffffff811fa317 ffff882f73e83820 ffff882f73e838a8
[ 4494.717221] Call Trace:
[ 4494.721649]  [<ffffffff81184faf>] shmem_evict_inode+0x7f/0x130
[ 4494.729873]  [<ffffffff811fa317>] evict+0xa7/0x170
[ 4494.736954]  [<ffffffff811fab55>] iput+0xf5/0x180
[ 4494.743935]  [<ffffffff81261208>] devpts_del_ref+0x28/0x40
[ 4494.751810]  [<ffffffff813b8756>] pty_unix98_shutdown+0x36/0x50
[ 4494.760188]  [<ffffffff813ad5c7>] release_tty+0x37/0x140
[ 4494.767898]  [<ffffffff813af8a4>] tty_release+0x4a4/0x5d0
[ 4494.775690]  [<ffffffff811e05a9>] __fput+0xe9/0x270
[ 4494.782910]  [<ffffffff811e086e>] ____fput+0xe/0x10
[ 4494.790147]  [<ffffffff810a22d7>] task_work_run+0xa7/0xe0
[ 4494.797982]  [<ffffffff81014b12>] do_notify_resume+0x92/0xb0
[ 4494.806187]  [<ffffffff8164647d>] int_signal+0x12/0x17
[ 4494.813782] Code: 54 4a 03 00 48 8b 85 10 ff ff ff eb c8 e8 f6 a0 ef ff 66 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 41 54 53 48 8b 9f 50 03 00 00 <48> 83 7b 30 00 74 19 4c 8d 63 40 4c 89 e7 e8 8a c4 4b 00 48 83
[ 4494.839542] RIP  [<ffffffff81180f13>] shmem_free_inode+0x13/0x40
[ 4494.848188]  RSP <ffff885f695e7d18>
[ 4494.853964] CR2: 0000000000000030