Why do RHEL 5.7 systems display "WARNING: at mm/vmalloc.c:329 __vunmap()" and hang ?

Issue

• RHEL 5.7 instances randomly display the following error and call trace.

kernel: Trying to vfree() nonexistent vm area (ffff8102ce540000)
kernel: WARNING: at mm/vmalloc.c:329 __vunmap()
kernel:
kernel: Call Trace:
kernel:  [<ffffffff800454f0>] __free_fdtable+0x1c/0x30
kernel:  [<ffffffff800efd9a>] free_fdtable_work+0x36/0x43
kernel:  [<ffffffff8004d311>] run_workqueue+0x9e/0xfb
kernel:  [<ffffffff80049b20>] worker_thread+0x0/0x122
kernel:  [<ffffffff80049c10>] worker_thread+0xf0/0x122
kernel:  [<ffffffff8008e857>] default_wake_function+0x0/0xe
kernel:  [<ffffffff80032722>] kthread+0xfe/0x132
kernel:  [<ffffffff8005dfb1>] child_rip+0xa/0x11
kernel:  [<ffffffff80032624>] kthread+0x0/0x132
kernel:  [<ffffffff8005dfa7>] child_rip+0x0/0x11

• RHEL 5.7 instances randomly hang.