I get the same kernel error but with kernel 2.6.22-14, in gutsy. I'm using a pentium 4 cpu. This bug may be a duplicate (or vice-versa) of bug #123223. I get random freeze every 1-2 day or so. Last time my system crash was just after starting firefox. The system memory was far from full (about 500 mb used in cache). System froze hard, after reboot I saw this in syslog :
Oct 11 20:43:19 nec kernel: [29991.443174] Eeek! page_mapcount(page) went negative! (-1)
Oct 11 20:43:19 nec kernel: [29991.443196] page pfn = 2ece0
Oct 11 20:43:19 nec kernel: [29991.443200] page->flags = 40000824
Oct 11 20:43:19 nec kernel: [29991.443203] page->count = 2
Oct 11 20:43:19 nec kernel: [29991.443206] page->mapping = effe4654
Oct 11 20:43:19 nec kernel: [29991.443223] vma->vm_ops = generic_file_vm_ops+0x0/0x18
Oct 11 20:43:19 nec kernel: [29991.443237] vma->vm_ops->nopage = filemap_nopage+0x0/0x340
Oct 11 20:43:19 nec kernel: [29991.443243] vma->vm_file->f_op->mmap = generic_file_mmap+0x0/0x40
Oct 11 20:43:19 nec kernel: [29991.443313] ------------[ cut here ]------------
Oct 11 20:43:19 nec kernel: [29991.443316] kernel BUG at /build/buildd/linux-source-2.6.22-2.6.22/mm/rmap.c:628!
Oct 11 20:43:19 nec kernel: [29991.443321] invalid opcode: 0000 [#1]
Oct 11 20:43:19 nec kernel: [29991.443324] SMP
Oct 11 20:43:19 nec kernel: [29991.443328] Modules linked in: vmnet(P) vmmon(P) binfmt_misc rfcomm l2cap bluetooth ppdev r128 drm cpufreq_stats cpufreq_ondemand cpufreq_powersave cpufreq_conservative cpufreq_userspace ac button container dock sbs video battery parport_pc lp parport p4_clockmod speedstep_lib freq_table snd_via82xx gameport snd_ac97_codec ac97_bus snd_pcm_oss snd_mixer_oss snd_pcm snd_page_alloc snd_mpu401_uart snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device i2c_viapro i2c_core via_ircc snd pcspkr psmouse serio_raw soundcore via_agp irda shpchp pci_hotplug agpgart crc_ccitt ipv6 nls_cp437 nls_utf8 cifs evdev ext3 jbd mbcache ide_cd cdrom ide_disk ata_generic libata scsi_mod via_rhine mii floppy via82cxxx ide_core uhci_hcd usbcore thermal processor fan fuse apparmor commoncap
Oct 11 20:43:19 nec kernel: [29991.443438] CPU: 0
Oct 11 20:43:19 nec kernel: [29991.443439] EIP: 0060:[page_remove_rmap+233/256] Tainted: P VLI
Oct 11 20:43:19 nec kernel: [29991.443441] EFLAGS: 00213282 (2.6.22-14-generic #1)
Oct 11 20:43:19 nec kernel: [29991.443452] EIP is at page_remove_rmap+0xe9/0x100
Oct 11 20:43:19 nec kernel: [29991.443457] eax: 0000004a ebx: c15d9c00 ecx: 00203046 edx: 00000000
Oct 11 20:43:19 nec kernel: [29991.443462] esi: dfe0b8f0 edi: b7d71000 ebp: dfeda380 esp: df941dc8
Oct 11 20:43:19 nec kernel: [29991.443466] ds: 007b es: 007b fs: 00d8 gs: 0000 ss: 0068
Oct 11 20:43:19 nec kernel: [29991.443471] Process Xorg (pid: 4493, ti=df940000 task=dfacc530 task.ti=df940000)
Oct 11 20:43:19 nec kernel: [29991.443475] Stack: c037ae8d effe4654 c15d9c00 ef1465c4 c016b5c2 c019e13c 2ece0025 3882d12b
Oct 11 20:43:19 nec kernel: [29991.443487] b7ea4fff 00000000 dfe0b8f0 df941e5c 001dff20 00000000 00000001 b7ea5000
Oct 11 20:43:19 nec kernel: [29991.443499] dfab9b7c c16092c0 0000a6df 00000000 00000000 ffffffef c15e28cc 00000000
Oct 11 20:43:19 nec kernel: [29991.443510] Call Trace:
Oct 11 20:43:19 nec kernel: [29991.443528] [unmap_vmas+770/1488] unmap_vmas+0x302/0x5d0
Oct 11 20:43:19 nec kernel: [29991.443535] [__mark_inode_dirty+92/400] __mark_inode_dirty+0x5c/0x190
Oct 11 20:43:19 nec kernel: [29991.443633] [exit_mmap+120/240] exit_mmap+0x78/0xf0
Oct 11 20:43:19 nec kernel: [29991.443667] [mmput+56/160] mmput+0x38/0xa0
Oct 11 20:43:19 nec kernel: [29991.443682] [do_exit+271/2064] do_exit+0x10f/0x810
Oct 11 20:43:19 nec kernel: [29991.443746] [do_group_exit+38/128] do_group_exit+0x26/0x80
Oct 11 20:43:19 nec kernel: [29991.443762] [get_signal_to_deliver+664/1040] get_signal_to_deliver+0x298/0x410
Oct 11 20:43:19 nec kernel: [29991.443789] [do_page_fault+0/1680] do_page_fault+0x0/0x690
Oct 11 20:43:19 nec kernel: [29991.443805] [do_notify_resume+147/1824] do_notify_resume+0x93/0x720
Oct 11 20:43:19 nec kernel: [29991.443877] [<f0ca8f17>] drm_vbl_send_signals+0x17/0xe0 [drm]
Oct 11 20:43:19 nec kernel: [29991.443926] [atomic_notifier_call_chain+23/32] atomic_notifier_call_chain+0x17/0x20
Oct 11 20:43:19 nec kernel: [29991.443940] [do_page_fault+1011/1680] do_page_fault+0x3f3/0x690
Oct 11 20:43:19 nec kernel: [29991.443950] [handle_IRQ_event+48/96] handle_IRQ_event+0x30/0x60
Oct 11 20:43:19 nec kernel: [29991.443963] [enable_8259A_irq+13/80] enable_8259A_irq+0xd/0x50
Oct 11 20:43:19 nec kernel: [29991.444011] [do_page_fault+0/1680] do_page_fault+0x0/0x690
Oct 11 20:43:19 nec kernel: [29991.444021] [work_notifysig+19/37] work_notifysig+0x13/0x25
Oct 11 20:43:19 nec kernel: [29991.444088] =======================
Oct 11 20:43:19 nec kernel: [29991.444091] Code: c0 74 0d 8b 50 08 b8 88 9e 37 c0 e8 12 ad fd ff 8b 46 48 85 c0 74 14 8b 40 10 85 c0 74 0d 8b 50 2c b8 a8 9e 37 c0 e8 f7 ac fd ff <0f> 0b eb fe 8b 53 0c eb 95 8d b4 26 00 00 00 00 8d bc 27 00 00
Oct 11 20:43:19 nec kernel: [29991.444152] EIP: [page_remove_rmap+233/256] page_remove_rmap+0xe9/0x100 SS:ESP 0068:df941dc8
Oct 11 20:43:19 nec kernel: [29991.444165] Fixing recursive fault but reboot is needed!
Oct 11 20:43:19 nec kernel: [29991.444183] BUG: scheduling while atomic: Xorg/0x00000001/4493
Oct 11 20:43:19 nec kernel: [29991.444191] [schedule+1243/2192] schedule+0x4db/0x890
Oct 11 20:43:19 nec kernel: [29991.444218] [__slab_free+273/672] __slab_free+0x111/0x2a0
Oct 11 20:43:19 nec kernel: [29991.444260] [cfq_free_io_context+41/160] cfq_free_io_context+0x29/0xa0
Oct 11 20:43:19 nec kernel: [29991.444301] [do_exit+1896/2064] do_exit+0x768/0x810
Oct 11 20:43:19 nec kernel: [29991.444361] [die+607/608] die+0x25f/0x260
Oct 11 20:43:19 nec kernel: [29991.444388] [do_invalid_op+0/144] do_invalid_op+0x0/0x90
Oct 11 20:43:19 nec kernel: [29991.444397] [do_invalid_op+129/144] do_invalid_op+0x81/0x90
Oct 11 20:43:19 nec kernel: [29991.444427] [page_remove_rmap+233/256] page_remove_rmap+0xe9/0x100
Oct 11 20:43:19 nec kernel: [29991.444438] [__call_console_drivers+83/96] __call_console_drivers+0x53/0x60
Oct 11 20:43:19 nec kernel: [29991.444458] [release_console_sem+455/496] release_console_sem+0x1c7/0x1f0
Oct 11 20:43:19 nec kernel: [29991.444542] [error_code+114/128] error_code+0x72/0x80
Oct 11 20:43:19 nec kernel: [29991.444584] [page_remove_rmap+233/256] page_remove_rmap+0xe9/0x100
Oct 11 20:43:19 nec kernel: [29991.444611] [unmap_vmas+770/1488] unmap_vmas+0x302/0x5d0
Oct 11 20:43:19 nec kernel: [29991.444618] [__mark_inode_dirty+92/400] __mark_inode_dirty+0x5c/0x190
Oct 11 20:43:19 nec kernel: [29991.444711] [exit_mmap+120/240] exit_mmap+0x78/0xf0
Oct 11 20:43:19 nec kernel: [29991.444745] [mmput+56/160] mmput+0x38/0xa0
Oct 11 20:43:19 nec kernel: [29991.444757] [do_exit+271/2064] do_exit+0x10f/0x810
Oct 11 20:43:19 nec kernel: [29991.444817] [do_group_exit+38/128] do_group_exit+0x26/0x80
Oct 11 20:43:19 nec kernel: [29991.444834] [get_signal_to_deliver+664/1040] get_signal_to_deliver+0x298/0x410
Oct 11 20:43:19 nec kernel: [29991.444859] [do_page_fault+0/1680] do_page_fault+0x0/0x690
Oct 11 20:43:19 nec kernel: [29991.444870] [do_notify_resume+147/1824] do_notify_resume+0x93/0x720
Oct 11 20:43:19 nec kernel: [29991.444940] [<f0ca8f17>] drm_vbl_send_signals+0x17/0xe0 [drm]
Oct 11 20:43:19 nec kernel: [29991.444975] [atomic_notifier_call_chain+23/32] atomic_notifier_call_chain+0x17/0x20
Oct 11 20:43:19 nec kernel: [29991.444989] [do_page_fault+1011/1680] do_page_fault+0x3f3/0x690
Oct 11 20:43:19 nec kernel: [29991.444999] [handle_IRQ_event+48/96] handle_IRQ_event+0x30/0x60
Oct 11 20:43:19 nec kernel: [29991.445013] [enable_8259A_irq+13/80] enable_8259A_irq+0xd/0x50
Oct 11 20:43:19 nec kernel: [29991.445060] [do_page_fault+0/1680] do_page_fault+0x0/0x690
Oct 11 20:43:19 nec kernel: [29991.445070] [work_notifysig+19/37] work_notifysig+0x13/0x25
Oct 11 20:43:19 nec kernel: [29991.445136] =======================
Oct 11 20:45:37 nec syslogd 1.4.1#21ubuntu3: restart.
Oct 11 20:45:37 nec kernel: Inspecting /boot/System.map-2.6.22-14-generic
Oct 11 20:45:38 nec kernel: Loaded 25445 symbols from /boot/System.map-2.6.22-14-generic.
Oct 11 20:45:38 nec kernel: Symbols match kernel version 2.6.22.
Oct 11 20:45:38 nec kernel: No module symbols loaded - kernel modules not enabled.
Oct 11 20:45:38 nec kernel: [ 0.000000] Linux version 2.6.22-14-generic (buildd@vernadsky) (gcc version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)) #1 SMP Wed Oct 10 06:00:47 GMT 2007 (Ubuntu 2.6.22-14.43-generic)
I get the same kernel error but with kernel 2.6.22-14, in gutsy. I'm using a pentium 4 cpu. This bug may be a duplicate (or vice-versa) of bug #123223. I get random freeze every 1-2 day or so. Last time my system crash was just after starting firefox. The system memory was far from full (about 500 mb used in cache). System froze hard, after reboot I saw this in syslog :
Oct 11 20:43:19 nec kernel: [29991.443174] Eeek! page_mapcount(page) went negative! (-1) file_vm_ ops+0x0/ 0x18 nopage+ 0x0/0x340 file->f_ op->mmap = generic_ file_mmap+ 0x0/0x40 buildd/ linux-source- 2.6.22- 2.6.22/ mm/rmap. c:628! conservative cpufreq_userspace ac button container dock sbs video battery parport_pc lp parport p4_clockmod speedstep_lib freq_table snd_via82xx gameport snd_ac97_codec ac97_bus snd_pcm_oss snd_mixer_oss snd_pcm snd_page_alloc snd_mpu401_uart snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device i2c_viapro i2c_core via_ircc snd pcspkr psmouse serio_raw soundcore via_agp irda shpchp pci_hotplug agpgart crc_ccitt ipv6 nls_cp437 nls_utf8 cifs evdev ext3 jbd mbcache ide_cd cdrom ide_disk ata_generic libata scsi_mod via_rhine mii floppy via82cxxx ide_core uhci_hcd usbcore thermal processor fan fuse apparmor commoncap remove_ rmap+233/ 256] Tainted: P VLI rmap+0xe9/ 0x100 vmas+770/ 1488] unmap_vmas+ 0x302/0x5d0 inode_dirty+ 92/400] __mark_ inode_dirty+ 0x5c/0x190 exit+38/ 128] do_group_ exit+0x26/ 0x80 to_deliver+ 664/1040] get_signal_ to_deliver+ 0x298/0x410 fault+0/ 1680] do_page_ fault+0x0/ 0x690 resume+ 147/1824] do_notify_ resume+ 0x93/0x720 send_signals+ 0x17/0xe0 [drm] notifier_ call_chain+ 23/32] atomic_ notifier_ call_chain+ 0x17/0x20 fault+1011/ 1680] do_page_ fault+0x3f3/ 0x690 IRQ_event+ 48/96] handle_ IRQ_event+ 0x30/0x60 8259A_irq+ 13/80] enable_ 8259A_irq+ 0xd/0x50 fault+0/ 1680] do_page_ fault+0x0/ 0x690 +19/37] work_notifysig+ 0x13/0x25 ======= ======= == rmap+233/ 256] page_remove_ rmap+0xe9/ 0x100 SS:ESP 0068:df941dc8 /4493 1243/2192] schedule+ 0x4db/0x890 free+273/ 672] __slab_ free+0x111/ 0x2a0 io_context+ 41/160] cfq_free_ io_context+ 0x29/0xa0 op+0/144] do_invalid_ op+0x0/ 0x90 op+129/ 144] do_invalid_ op+0x81/ 0x90 rmap+233/ 256] page_remove_ rmap+0xe9/ 0x100 console_ drivers+ 83/96] __call_ console_ drivers+ 0x53/0x60 console_ sem+455/ 496] release_ console_ sem+0x1c7/ 0x1f0 code+114/ 128] error_code+ 0x72/0x80 rmap+233/ 256] page_remove_ rmap+0xe9/ 0x100 vmas+770/ 1488] unmap_vmas+ 0x302/0x5d0 inode_dirty+ 92/400] __mark_ inode_dirty+ 0x5c/0x190 exit+38/ 128] do_group_ exit+0x26/ 0x80 to_deliver+ 664/1040] get_signal_ to_deliver+ 0x298/0x410 fault+0/ 1680] do_page_ fault+0x0/ 0x690 resume+ 147/1824] do_notify_ resume+ 0x93/0x720 send_signals+ 0x17/0xe0 [drm] notifier_ call_chain+ 23/32] atomic_ notifier_ call_chain+ 0x17/0x20 fault+1011/ 1680] do_page_ fault+0x3f3/ 0x690 IRQ_event+ 48/96] handle_ IRQ_event+ 0x30/0x60 8259A_irq+ 13/80] enable_ 8259A_irq+ 0xd/0x50 fault+0/ 1680] do_page_ fault+0x0/ 0x690 +19/37] work_notifysig+ 0x13/0x25 ======= ======= == map-2.6. 22-14-generic map-2.6. 22-14-generic. 14.43-generic)
Oct 11 20:43:19 nec kernel: [29991.443196] page pfn = 2ece0
Oct 11 20:43:19 nec kernel: [29991.443200] page->flags = 40000824
Oct 11 20:43:19 nec kernel: [29991.443203] page->count = 2
Oct 11 20:43:19 nec kernel: [29991.443206] page->mapping = effe4654
Oct 11 20:43:19 nec kernel: [29991.443223] vma->vm_ops = generic_
Oct 11 20:43:19 nec kernel: [29991.443237] vma->vm_ops->nopage = filemap_
Oct 11 20:43:19 nec kernel: [29991.443243] vma->vm_
Oct 11 20:43:19 nec kernel: [29991.443313] ------------[ cut here ]------------
Oct 11 20:43:19 nec kernel: [29991.443316] kernel BUG at /build/
Oct 11 20:43:19 nec kernel: [29991.443321] invalid opcode: 0000 [#1]
Oct 11 20:43:19 nec kernel: [29991.443324] SMP
Oct 11 20:43:19 nec kernel: [29991.443328] Modules linked in: vmnet(P) vmmon(P) binfmt_misc rfcomm l2cap bluetooth ppdev r128 drm cpufreq_stats cpufreq_ondemand cpufreq_powersave cpufreq_
Oct 11 20:43:19 nec kernel: [29991.443438] CPU: 0
Oct 11 20:43:19 nec kernel: [29991.443439] EIP: 0060:[page_
Oct 11 20:43:19 nec kernel: [29991.443441] EFLAGS: 00213282 (2.6.22-14-generic #1)
Oct 11 20:43:19 nec kernel: [29991.443452] EIP is at page_remove_
Oct 11 20:43:19 nec kernel: [29991.443457] eax: 0000004a ebx: c15d9c00 ecx: 00203046 edx: 00000000
Oct 11 20:43:19 nec kernel: [29991.443462] esi: dfe0b8f0 edi: b7d71000 ebp: dfeda380 esp: df941dc8
Oct 11 20:43:19 nec kernel: [29991.443466] ds: 007b es: 007b fs: 00d8 gs: 0000 ss: 0068
Oct 11 20:43:19 nec kernel: [29991.443471] Process Xorg (pid: 4493, ti=df940000 task=dfacc530 task.ti=df940000)
Oct 11 20:43:19 nec kernel: [29991.443475] Stack: c037ae8d effe4654 c15d9c00 ef1465c4 c016b5c2 c019e13c 2ece0025 3882d12b
Oct 11 20:43:19 nec kernel: [29991.443487] b7ea4fff 00000000 dfe0b8f0 df941e5c 001dff20 00000000 00000001 b7ea5000
Oct 11 20:43:19 nec kernel: [29991.443499] dfab9b7c c16092c0 0000a6df 00000000 00000000 ffffffef c15e28cc 00000000
Oct 11 20:43:19 nec kernel: [29991.443510] Call Trace:
Oct 11 20:43:19 nec kernel: [29991.443528] [unmap_
Oct 11 20:43:19 nec kernel: [29991.443535] [__mark_
Oct 11 20:43:19 nec kernel: [29991.443633] [exit_mmap+120/240] exit_mmap+0x78/0xf0
Oct 11 20:43:19 nec kernel: [29991.443667] [mmput+56/160] mmput+0x38/0xa0
Oct 11 20:43:19 nec kernel: [29991.443682] [do_exit+271/2064] do_exit+0x10f/0x810
Oct 11 20:43:19 nec kernel: [29991.443746] [do_group_
Oct 11 20:43:19 nec kernel: [29991.443762] [get_signal_
Oct 11 20:43:19 nec kernel: [29991.443789] [do_page_
Oct 11 20:43:19 nec kernel: [29991.443805] [do_notify_
Oct 11 20:43:19 nec kernel: [29991.443877] [<f0ca8f17>] drm_vbl_
Oct 11 20:43:19 nec kernel: [29991.443926] [atomic_
Oct 11 20:43:19 nec kernel: [29991.443940] [do_page_
Oct 11 20:43:19 nec kernel: [29991.443950] [handle_
Oct 11 20:43:19 nec kernel: [29991.443963] [enable_
Oct 11 20:43:19 nec kernel: [29991.444011] [do_page_
Oct 11 20:43:19 nec kernel: [29991.444021] [work_notifysig
Oct 11 20:43:19 nec kernel: [29991.444088] =======
Oct 11 20:43:19 nec kernel: [29991.444091] Code: c0 74 0d 8b 50 08 b8 88 9e 37 c0 e8 12 ad fd ff 8b 46 48 85 c0 74 14 8b 40 10 85 c0 74 0d 8b 50 2c b8 a8 9e 37 c0 e8 f7 ac fd ff <0f> 0b eb fe 8b 53 0c eb 95 8d b4 26 00 00 00 00 8d bc 27 00 00
Oct 11 20:43:19 nec kernel: [29991.444152] EIP: [page_remove_
Oct 11 20:43:19 nec kernel: [29991.444165] Fixing recursive fault but reboot is needed!
Oct 11 20:43:19 nec kernel: [29991.444183] BUG: scheduling while atomic: Xorg/0x00000001
Oct 11 20:43:19 nec kernel: [29991.444191] [schedule+
Oct 11 20:43:19 nec kernel: [29991.444218] [__slab_
Oct 11 20:43:19 nec kernel: [29991.444260] [cfq_free_
Oct 11 20:43:19 nec kernel: [29991.444301] [do_exit+1896/2064] do_exit+0x768/0x810
Oct 11 20:43:19 nec kernel: [29991.444361] [die+607/608] die+0x25f/0x260
Oct 11 20:43:19 nec kernel: [29991.444388] [do_invalid_
Oct 11 20:43:19 nec kernel: [29991.444397] [do_invalid_
Oct 11 20:43:19 nec kernel: [29991.444427] [page_remove_
Oct 11 20:43:19 nec kernel: [29991.444438] [__call_
Oct 11 20:43:19 nec kernel: [29991.444458] [release_
Oct 11 20:43:19 nec kernel: [29991.444542] [error_
Oct 11 20:43:19 nec kernel: [29991.444584] [page_remove_
Oct 11 20:43:19 nec kernel: [29991.444611] [unmap_
Oct 11 20:43:19 nec kernel: [29991.444618] [__mark_
Oct 11 20:43:19 nec kernel: [29991.444711] [exit_mmap+120/240] exit_mmap+0x78/0xf0
Oct 11 20:43:19 nec kernel: [29991.444745] [mmput+56/160] mmput+0x38/0xa0
Oct 11 20:43:19 nec kernel: [29991.444757] [do_exit+271/2064] do_exit+0x10f/0x810
Oct 11 20:43:19 nec kernel: [29991.444817] [do_group_
Oct 11 20:43:19 nec kernel: [29991.444834] [get_signal_
Oct 11 20:43:19 nec kernel: [29991.444859] [do_page_
Oct 11 20:43:19 nec kernel: [29991.444870] [do_notify_
Oct 11 20:43:19 nec kernel: [29991.444940] [<f0ca8f17>] drm_vbl_
Oct 11 20:43:19 nec kernel: [29991.444975] [atomic_
Oct 11 20:43:19 nec kernel: [29991.444989] [do_page_
Oct 11 20:43:19 nec kernel: [29991.444999] [handle_
Oct 11 20:43:19 nec kernel: [29991.445013] [enable_
Oct 11 20:43:19 nec kernel: [29991.445060] [do_page_
Oct 11 20:43:19 nec kernel: [29991.445070] [work_notifysig
Oct 11 20:43:19 nec kernel: [29991.445136] =======
Oct 11 20:45:37 nec syslogd 1.4.1#21ubuntu3: restart.
Oct 11 20:45:37 nec kernel: Inspecting /boot/System.
Oct 11 20:45:38 nec kernel: Loaded 25445 symbols from /boot/System.
Oct 11 20:45:38 nec kernel: Symbols match kernel version 2.6.22.
Oct 11 20:45:38 nec kernel: No module symbols loaded - kernel modules not enabled.
Oct 11 20:45:38 nec kernel: [ 0.000000] Linux version 2.6.22-14-generic (buildd@vernadsky) (gcc version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)) #1 SMP Wed Oct 10 06:00:47 GMT 2007 (Ubuntu 2.6.22-