RHEL6: kernel crashes at d_materialise_unique() with `BUG at fs/dcache.c:1999!`

Issue

• Kernel crashes at d_materialise_unique() with following logs:

[418945.792092] ------------[ cut here ]------------
[418945.792116] kernel BUG at fs/dcache.c:1999!
[418945.792130] invalid opcode: 0000 [#1] SMP 
[418945.792540] last sysfs file: /sys/devices/system/cpu/online
[418945.792821] CPU 4 
[418945.792827] Modules linked in: tcp_diag inet_diag nfs lockd fscache auth_rpcgss nfs_acl sunrpc iptable_raw xt_time xt_recent xt_limit ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_iprange vsock(U) xt_set iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables ipv6 ip_set_hash_ip ip_set nfnetlink ext3 jbd microcode vmware_balloon vmci(U) i2c_piix4 sg shpchp ext4 jbd2 mbcache sd_mod crc_t10dif sr_mod cdrom vmxnet3 mptspi mptscsih mptbase scsi_transport_spi pata_acpi ata_generic ata_piix vmwgfx ttm drm_kms_helper drm i2c_core dm_mirror dm_region_hash dm_log dm_mod [last unloaded: speedstep_lib]
[418945.794796] 
[418945.795148] Pid: 114637, comm: php-cgi Not tainted 2.6.32-754.27.1.el6.x86_64 #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
[418945.795547] RIP: 0010:[<ffffffff811be958>]  [<ffffffff811be958>] d_materialise_unique+0x3e8/0x430
[418945.795958] RSP: 0018:ffff880108d5fa88  EFLAGS: 00010246
[418945.796367] RAX: ffffffff81a863c0 RBX: ffff88059afdb448 RCX: ffff8805c2f2f400
[418945.796791] RDX: ffff88062f72d800 RSI: ffff88062f72d8f8 RDI: ffff8803b84bf140
[418945.797222] RBP: ffff880108d5fac8 R08: ffff880116625e40 R09: ffff88059afdb448
[418945.797647] R10: 000000000000000b R11: 000000000000000b R12: ffff880116625e40
[418945.798081] R13: ffff88010092d0c0 R14: ffff88063384dc80 R15: ffff8803b84bf140
[418945.798514] FS:  00007f56ee7977e0(0000) GS:ffff88003f100000(0000) knlGS:0000000000000000
[418945.798961] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[418945.799415] CR2: 00007fe21bcb0c50 CR3: 0000000476430000 CR4: 00000000000607e0
[418945.799936] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[418945.800426] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[418945.800909] Process php-cgi (pid: 114637, threadinfo ffff880108d5c000, task ffff8801081aa040)
[418945.801403] Stack:
[418945.801876]  ffff88063384dc80 ffff88010092d0c0 ffff880116625e40 ffff8806311accf8
[418945.801896] <d> ffff880116625e40 ffff88010092d0c0 ffff88063384dc80 ffff880425770a40
[418945.802377] <d> ffff880108d5fb18 ffffffffa05c1bbb ffff880108d5fb28 ffff88059afdb448
[418945.803358] Call Trace:
[418945.803866]  [<ffffffffa05c1bbb>] nfs_lookup+0x1cb/0x220 [nfs]
[418945.804386]  [<ffffffffa05c1cfe>] nfs_atomic_lookup+0xee/0x330 [nfs]
[418945.804911]  [<ffffffff811b1b1b>] do_lookup+0x1ab/0x230
[418945.805439]  [<ffffffff811b26dc>] __link_path_walk+0x79c/0x1090
[418945.805982]  [<ffffffff811361c7>] ? mempool_free_slab+0x17/0x20
[418945.806531]  [<ffffffffa0523285>] ? rpc_final_put_task+0x55/0x60 [sunrpc]
[418945.807087]  [<ffffffffa05232c0>] ? rpc_do_put_task+0x30/0x40 [sunrpc]
[418945.807634]  [<ffffffff811b328a>] path_walk+0x6a/0xe0
[418945.808176]  [<ffffffff811b349b>] filename_lookup+0x6b/0xc0
[418945.808731]  [<ffffffff811b45c7>] user_path_at+0x57/0xa0
[418945.809333]  [<ffffffffa05c5d66>] ? __put_nfs_open_context+0xe6/0x120 [nfs]
[418945.809923]  [<ffffffff811a7740>] vfs_fstatat+0x50/0xa0
[418945.810575]  [<ffffffff811c4bd0>] ? mntput_no_expire+0x30/0x110
[418945.811183]  [<ffffffff811a77fe>] vfs_lstat+0x1e/0x20
[418945.811768]  [<ffffffff811a7824>] sys_newlstat+0x24/0x50
[418945.812380]  [<ffffffff810f3207>] ? audit_syscall_entry+0x1d7/0x200
[418945.812988]  [<ffffffff810f2ffe>] ? __audit_syscall_exit+0x25e/0x290
[418945.813618]  [<ffffffff815643a7>] system_call_fastpath+0x35/0x3a
[418945.814241] Code: 85 c0 75 2b 48 c7 45 c8 8c ff ff ff 49 c7 c7 8c ff ff ff 31 c0 e9 c1 fd ff ff 0f 0b eb fe 48 c7 c0 c0 63 a8 81 c7 00 00 00 00 00 <0f> 0b eb fe 49 8b 45 28 48 8b 40 10 48 05 b8 00 00 00 e9 35 fd 
[418945.815581] RIP  [<ffffffff811be958>] d_materialise_unique+0x3e8/0x430
[418945.816254]  RSP <ffff880108d5fa88>