Can't tell you what caused it exactly, but things were perfectly stable
until:
kernel: sh[17943]: segfault at 0000000000000000 rip 0000000000000000 rsp
00007fffffa020d0
error 14
kernel: ----------- [cut here ] --------- [please bite here ] ---------
kernel: Kernel BUG at "mm/rmap.c":493
kernel: invalid operand: 0000 [1] SMP
kernel: CPU 1
kernel: Modules linked in: md5 ipv6 autofs4 dm_mod video button battery ac
shpchp tg3
floppy ext3 jbd rai
d0 mv_sata(U) sd_mod scsi_mod
kernel: Pid: 17943, comm: sh Tainted: G M 2.6.11-1.1369_FC4smp
kernel: RIP: 0010:[<ffffffff8017bfa8>]
<ffffffff8017bfa8>{page_remove_rmap+40}
kernel: RSP: 0000:ffff81003b741c40 EFLAGS: 00010286
kernel: RAX: 00000000ffffffff RBX: 0000000000000020 RCX: ffff810042438440
kernel: RDX: ffff810018cc4120 RSI: ffff81003f51d8e8 RDI: ffff81000116a240
kernel: RBP: ffff81000116a240 R08: ffff81000116a240 R09: 00000000fffffffa
kernel: R10: ffff810000fabe28 R11: 0000000000000003 R12: ffff81002f1f3008
kernel: R13: 0000000000401000 R14: 00000000004a8000 R15: ffff810040e184a0
kernel: FS: 00002aaaab3381a0(0000) GS:ffffffff80510700(0000)
knlGS:00000000f7f249e0
kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
Ran memtest86 for a while and it doesn't appear to be a RAM issue...This is
on a dual Opteron 246 with 2 gigs ECC...