KVM上のサーバが止まる

生きている（ping 反応あるし、apacheも動作してる）んだけど、sshでログインするとなにも表示されない

作業していると急にsyslogdからメッセージがくる。

原因不明。とりあえず下記実行。

# yum update
# yum upgrade

/var/log/messages の内容（moriokaはホスト名）

Oct 10 06:30:12 morioka kernel: BUG: soft lockup - CPU#0 stuck for 36864s! [bash:1518]
Oct 10 06:30:12 morioka kernel: Modules linked in: ip6t_REJECT nf_conntrack_ipv6 ip6table_filter ip6_tables ipv6 joydev i2c_piix4 virtio_net virtio_balloon i2c_core virtio_blk virtio_pci virtio_ring virtio [last unloaded: scsi_wait_scan]
Oct 10 06:30:12 morioka kernel: CPU 0
Oct 10 06:30:12 morioka kernel: Pid: 1518, comm: bash Not tainted 2.6.33.3-85.fc13.x86_64 #1 /Bochs
Oct 10 06:30:12 morioka kernel: RIP: 0010:[<ffffffff810d8015>]  [<ffffffff810d8015>] unmap_vmas+0x4bc/0x845
Oct 10 06:30:12 morioka kernel: RSP: 0018:ffff88001d167b08  EFLAGS: 00000202
Oct 10 06:30:12 morioka kernel: RAX: 8000000010b9c045 RBX: ffff88001d167c38 RCX: 00003ffffffff000
Oct 10 06:30:12 morioka kernel: RDX: ffff88001f5b23b8 RSI: 00007f93f7477000 RDI: ffff880001e0e9a0
Oct 10 06:30:12 morioka kernel: RBP: ffffffff8100a4ce R08: ffff88001ce86dc0 R09: 0000000000000001
Oct 10 06:30:12 morioka kernel: R10: ffffffff81d7c040 R11: 00000000df00a8ed R12: ffff88001d167a88
Oct 10 06:30:12 morioka kernel: R13: 000000004cb04444 R14: ffffffff8111336f R15: ffff88001d167aa8
Oct 10 06:30:12 morioka kernel: FS:  00007f93f7692700(0000) GS:ffff880001e00000(0000) knlGS:0000000000000000
Oct 10 06:30:12 morioka kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
Oct 10 06:30:12 morioka kernel: CR2: 0000000000440060 CR3: 000000001d0f9000 CR4: 00000000000006f0
Oct 10 06:30:12 morioka kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Oct 10 06:30:12 morioka kernel: DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Oct 10 06:30:12 morioka kernel: Process bash (pid: 1518, threadinfo ffff88001d166000, task ffff88001d811750)
Oct 10 06:30:12 morioka kernel: Stack:
Oct 10 06:30:12 morioka kernel: 0000000000001000 ffffffffffffffff 0000000000000080 0000000000000001
Oct 10 06:30:12 morioka kernel: <0> 0000000000000080 0000000000000000 00007f93f747bfff 00007f93f747bfff
Oct 10 06:30:12 morioka kernel: <0> 00000001810fe8a7 ffff88001d167c48 0000000000400000 0000000000000000
Oct 10 06:30:12 morioka kernel: Call Trace:
Oct 10 06:30:12 morioka kernel: [<ffffffff810dd2a1>] ? exit_mmap+0xc9/0x12d
Oct 10 06:30:12 morioka kernel: [<ffffffff810490e3>] ? mmput+0x59/0xc5
Oct 10 06:30:12 morioka kernel: [<ffffffff81106db4>] ? flush_old_exec+0x4b4/0x589
Oct 10 06:30:12 morioka kernel: [<ffffffff8113b52d>] ? load_elf_binary+0x30e/0x15b1
Oct 10 06:30:12 morioka kernel: [<ffffffff81138de3>] ? load_misc_binary+0x6e/0x362
Oct 10 06:30:12 morioka kernel: [<ffffffff811065ab>] ? search_binary_handler+0xbb/0x26e
Oct 10 06:30:12 morioka kernel: [<ffffffff8113b21f>] ? load_elf_binary+0x0/0x15b1
Oct 10 06:30:12 morioka kernel: [<ffffffff81107c07>] ? do_execve+0x1c9/0x2ca
Oct 10 06:30:12 morioka kernel: [<ffffffff81010bd5>] ? sys_execve+0x3e/0x55
Oct 10 06:30:12 morioka kernel: [<ffffffff81009f5a>] ? stub_execve+0x6a/0xc0
Oct 10 06:30:12 morioka kernel: Code: 47 10 0f 82 bf 01 00 00 49 3b 47 18 0f 87 b5 01 00 00 48 8b 7d a0 83 7f 10 00 74 18 48 8b 45 c8 48 8b 55 c8 48 8b 00 48 89 45 80 <48> c7 02 00 00 00 00 eb 1f 48 8b 4d c8 31 f6 48 87 31 48 89 75
Oct 10 06:30:12 morioka kernel: Call Trace:
Oct 10 06:30:12 morioka kernel: [<ffffffff810d7fb0>] ? unmap_vmas+0x457/0x845
Oct 10 06:30:12 morioka kernel: [<ffffffff810dd2a1>] ? exit_mmap+0xc9/0x12d
Oct 10 06:30:12 morioka kernel: [<ffffffff810490e3>] ? mmput+0x59/0xc5
Oct 10 06:30:12 morioka kernel: [<ffffffff81106db4>] ? flush_old_exec+0x4b4/0x589
Oct 10 06:30:12 morioka kernel: [<ffffffff8113b52d>] ? load_elf_binary+0x30e/0x15b1
Oct 10 06:30:12 morioka kernel: [<ffffffff81138de3>] ? load_misc_binary+0x6e/0x362
Oct 10 06:30:12 morioka kernel: [<ffffffff811065ab>] ? search_binary_handler+0xbb/0x26e
Oct 10 06:30:12 morioka kernel: [<ffffffff8113b21f>] ? load_elf_binary+0x0/0x15b1
Oct 10 06:30:12 morioka kernel: [<ffffffff81107c07>] ? do_execve+0x1c9/0x2ca
Oct 10 06:30:12 morioka kernel: [<ffffffff81010bd5>] ? sys_execve+0x3e/0x55
Oct 10 06:30:12 morioka kernel: [<ffffffff81009f5a>] ? stub_execve+0x6a/0xc0