About "WARNING at fs/locks.c:2046 locks_remove_flock" message.

Issue

• The following message is logged in our customer's environment.
• /var/log/messages

Mar 12 17:12:20 server01 kernel: ------------[ cut here ]------------
Mar 12 17:12:20 server01 kernel: WARNING: at fs/locks.c:2046 locks_remove_flock+0x17a/0x180() (Not tainted)
Mar 12 17:12:20 server01 kernel: Hardware name: Express5800/R110d-1M [N8100-1806Y]
Mar 12 17:12:20 server01 kernel: leftover lock: dev=0:20 ino=20710075 type=0 flags=0x81 start=0 end=9223372036854775807
Mar 12 17:12:20 server01 kernel: Modules linked in: fuse splxmod(U) nfsd exportfs autofs4 nfs lockd fscache ... snip ...
Mar 12 17:12:20 server01 kernel: Pid: 22238, comm: zrefer.cgi Not tainted 2.6.32-504.el6.x86_64 #1
Mar 12 17:12:20 server01 kernel: Call Trace:
Mar 12 17:12:20 server01 kernel: [<ffffffff81074df7>] ? warn_slowpath_common+0x87/0xc0
Mar 12 17:12:20 server01 kernel: [<ffffffff81074ee6>] ? warn_slowpath_fmt+0x46/0x50
Mar 12 17:12:20 server01 kernel: [<ffffffffa0344c36>] ? nfs_flock+0xb6/0xf0 [nfs]
Mar 12 17:12:20 server01 kernel: [<ffffffff811df68a>] ? locks_remove_flock+0x17a/0x180
Mar 12 17:12:20 server01 kernel: [<ffffffff8118f8b0>] ? __fput+0xd0/0x210
Mar 12 17:12:20 server01 kernel: [<ffffffff8118fa15>] ? fput+0x25/0x30
Mar 12 17:12:20 server01 kernel: [<ffffffff8118ac6d>] ? filp_close+0x5d/0x90
Mar 12 17:12:20 server01 kernel: [<ffffffff8118ad45>] ? sys_close+0xa5/0x100
Mar 12 17:12:20 server01 kernel: [<ffffffffa041c306>] ? closeHook+0x166/0xbb0 [splxmod]
Mar 12 17:12:20 server01 kernel: [<ffffffff8122d446>] ? security_file_permission+0x16/0x20
Mar 12 17:12:20 server01 kernel: [<ffffffff8118e058>] ? vfs_write+0xb8/0x1a0
Mar 12 17:12:20 server01 kernel: [<ffffffff810e5c87>] ? audit_syscall_entry+0x1d7/0x200
Mar 12 17:12:20 server01 kernel: [<ffffffff810e5a7e>] ? __audit_syscall_exit+0x25e/0x290
Mar 12 17:12:20 server01 kernel: [<ffffffff8100b072>] ? system_call_fastpath+0x16/0x1b
Mar 12 17:12:20 server01 kernel: ---[ end trace e43020b68072eb6a ]---