なんで落ちたのか全然分からないけど、fdを10000個くらい開いていじめてたら固まった。うーん。
Nov 16 18:42:49 nausicaa kernel: [123845.138981] Eeek! page_mapcount(page) went negative! (-1)
Nov 16 18:42:49 nausicaa kernel: [123845.139035] page pfn = 13
Nov 16 18:42:49 nausicaa kernel: [123845.139064] page->flags = 400
Nov 16 18:42:49 nausicaa kernel: [123845.139093] page->count = 2
Nov 16 18:42:49 nausicaa kernel: [123845.139121] page->mapping = 0000000000000000
Nov 16 18:42:49 nausicaa kernel: [123845.139169] vma->vm_ops = 0x0
Nov 16 18:42:49 nausicaa kernel: [123845.139219] ------------[ cut here ]------------
Nov 16 18:42:49 nausicaa kernel: [123845.139251] kernel BUG at mm/rmap.c:669!
Nov 16 18:42:49 nausicaa kernel: [123845.139281] invalid opcode: 0000 [1] SMP
Nov 16 18:42:49 nausicaa kernel: [123845.139326] CPU 0
Nov 16 18:42:49 nausicaa kernel: [123845.139360] Modules linked in: bridge video output ac battery ipv6 xfs loop ns558 snd_mpu401 parport_pc parport snd_via82xx gameport k8temp snd_ac97_codec ac97_bus snd_pcm snd_timer snd_page_alloc snd_mpu401_uart snd_rawmidi snd_seq_device pcspkr snd soundcore i2c_viapro i2c_core button shpchp pci_hotplug evdev ext3 jbd mbcache usbhid hid ff_memless ide_disk ide_cd_mod cdrom ide_pci_generic via82cxxx ide_core floppy ehci_hcd sata_via ata_generic libata uhci_hcd scsi_mod dock ohci1394 r8169 ieee1394 thermal processor fan thermal_sys
Nov 16 18:42:49 nausicaa kernel: [123845.139988] Pid: 16758, comm: beam Not tainted 2.6.26-1-xen-amd64 #1
Nov 16 18:42:49 nausicaa kernel: [123845.140043] RIP: e030:[] [ ] page_remove_rmap+0xfb/0x117
Nov 16 18:42:49 nausicaa kernel: [123845.140043] RSP: e02b:ffff880007515df8 EFLAGS: 00010246
Nov 16 18:42:49 nausicaa kernel: [123845.140043] RAX: 0000000000000000 RBX: ffff880001c15428 RCX: 0000e2e200008dd7
Nov 16 18:42:49 nausicaa kernel: [123845.140043] RDX: ffffffffff5f7000 RSI: 0000000000000001 RDI: ffffffff805aaab0
Nov 16 18:42:49 nausicaa kernel: [123845.140043] RBP: ffff88000758b528 R08: 0000000000000024 R09: ffff880007515800
Nov 16 18:42:49 nausicaa kernel: [123845.140043] R10: 0000000000000000 R11: 000001a06123da17 R12: ffff880001c15428
Nov 16 18:42:49 nausicaa kernel: [123845.140043] R13: 0000000000000008 R14: ffff8800378dcb00 R15: ffff88000758b528
Nov 16 18:42:49 nausicaa kernel: [123845.140043] FS: 00007fa2c7be06e0(0000) GS:ffffffff80539000(0000) knlGS:0000000000000000
Nov 16 18:42:49 nausicaa kernel: [123845.140043] CS: e033 DS: 0000 ES: 0000
Nov 16 18:42:49 nausicaa kernel: [123845.140043] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Nov 16 18:42:49 nausicaa kernel: [123845.140043] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Nov 16 18:42:49 nausicaa kernel: [123845.140043] Process beam (pid: 16758, threadinfo ffff880007514000, task ffff8800383d2140)
Nov 16 18:42:49 nausicaa kernel: [123845.140043] Stack: 00007fa2c09ecb18 800000002a5f0067 ffff88000205fc80 ffffffff80272468
Nov 16 18:42:49 nausicaa kernel: [123845.140043] ffff880002595368 ffff880007420020 ffff88002ac04f60 ffff88000256f0f0
Nov 16 18:42:49 nausicaa kernel: [123845.140043] ffff88002ac04f60 ffff88000256f0f0 ffff88002ac04f60 0000000000000006
Nov 16 18:42:49 nausicaa kernel: [123845.140043] Call Trace:
Nov 16 18:42:49 nausicaa kernel: [123845.140043] [] ? do_wp_page+0x6cf/0x789
Nov 16 18:42:49 nausicaa kernel: [123845.140043] [] ? handle_mm_fault+0xbcb/0xc49
Nov 16 18:42:49 nausicaa kernel: [123845.140043] [] ? _spin_lock_bh+0xe/0x48
Nov 16 18:42:49 nausicaa kernel: [123845.140043] [] ? do_page_fault+0xb73/0xf50
Nov 16 18:42:49 nausicaa kernel: [123845.140043] [] ? error_exit+0x0/0x69
Nov 16 18:42:49 nausicaa kernel: [123845.140043]
Nov 16 18:42:49 nausicaa kernel: [123845.140043]
Nov 16 18:42:49 nausicaa kernel: [123845.140043] Code: 80 e8 3c 0c fd ff 48 8b 85 90 00 00 00 48 85 c0 74 19 48 8b 40 20 48 85 c0 74 10 48 8b 70 58 48 c7 c7 66 52 4b 80 e8 17 0c fd ff <0f> 0b eb fe 8b 77 18 41 58 5b 5d 83 e6 01 f7 de 83 c6 04 e9 6c
Nov 16 18:42:49 nausicaa kernel: [123845.140043] RIP [] page_remove_rmap+0xfb/0x117
Nov 16 18:42:49 nausicaa kernel: [123845.140043] RSP
Nov 16 18:42:49 nausicaa kernel: [123845.144086] ---[ end trace 423069b0410a3d2e ]---