Re: kernel BUG at mm/vmscan.c:1114

[Mel Gorman]

On Wed, Aug 03, 2011 at 02:44:20PM +0800, Xiaotian Feng wrote:
> On Tue, Aug 2, 2011 at 3:22 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> > On Tue, 2 Aug 2011 15:09:57 +0800 Xiaotian Feng <xtfeng@xxxxxxxxx> wrote:
> >
> >> __ __I'm hitting the kernel BUG at mm/vmscan.c:1114 twice, each time I
> >> was trying to build my kernel. The photo of crash screen and my config
> >> is attached.
> >
> > hm, now why has that started happening?
> >
> > Perhaps you could apply this debug patch, see if we can narrow it down?
> >
> 
> I will try it then, but it isn't very reproducible :(
> But my system hung after some list corruption warnings... I hit the
> corruption 4 times...
> 

That is very unexpected but if lists are being corrupted, it could
explain the previously reported bug as that bug looked like an active
page on an inactive list.

What was the last working kernel? Can you bisect?

>  [ 1220.468089] ------------[ cut here ]------------
>  [ 1220.468099] WARNING: at lib/list_debug.c:56 __list_del_entry+0x82/0xd0()
>  [ 1220.468102] Hardware name: 42424XC
>  [ 1220.468104] list_del corruption. next->prev should be
> ffffea0000e069a0, but was ffff880100216c78
>  [ 1220.468106] Modules linked in: ip6table_filter ip6_tables
> ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4
> xt_state nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle xt_tcpudp
> iptable_filter ip_tables x_tables binfmt_misc bridge stp parport_pc
> ppdev snd_hda_codec_conexant snd_hda_intel snd_hda_codec thinkpad_acpi
> snd_hwdep snd_pcm i915 snd_seq_midi snd_rawmidi arc4 cryptd
> snd_seq_midi_event aes_x86_64 snd_seq drm_kms_helper iwlagn snd_timer
> aes_generic drm snd_seq_device mac80211 psmouse uvcvideo videodev snd
> v4l2_compat_ioctl32 soundcore snd_page_alloc serio_raw i2c_algo_bit
> btusb tpm_tis tpm tpm_bios video cfg80211 bluetooth nvram lp joydev
> parport usbhid hid ahci libahci firewire_ohci firewire_core e1000e
> sdhci_pci sdhci crc_itu_t
>  [ 1220.468185] Pid: 1168, comm: Xorg Tainted: G        W   3.0.0+ #23
>  [ 1220.468188] Call Trace:
>  [ 1220.468190]  <IRQ>  [<ffffffff8106db3f>] warn_slowpath_common+0x7f/0xc0
>  [ 1220.468201]  [<ffffffff8106dc36>] warn_slowpath_fmt+0x46/0x50
>  [ 1220.468206]  [<ffffffff81332a52>] __list_del_entry+0x82/0xd0
>  [ 1220.468210]  [<ffffffff81332ab1>] list_del+0x11/0x40
>  [ 1220.468216]  [<ffffffff8117a212>] __slab_free+0x362/0x3d0
>  [ 1220.468222]  [<ffffffff811c6606>] ? bvec_free_bs+0x26/0x40
>  [ 1220.468226]  [<ffffffff8117b767>] ? kmem_cache_free+0x97/0x220
>  [ 1220.468230]  [<ffffffff811c6606>] ? bvec_free_bs+0x26/0x40
>  [ 1220.468234]  [<ffffffff811c6606>] ? bvec_free_bs+0x26/0x40
>  [ 1220.468239]  [<ffffffff8117b8df>] kmem_cache_free+0x20f/0x220
>  [ 1220.468243]  [<ffffffff811c6606>] bvec_free_bs+0x26/0x40
>  [ 1220.468247]  [<ffffffff811c6654>] bio_free+0x34/0x70
>  [ 1220.468250]  [<ffffffff811c66a5>] bio_fs_de
> 

This warning and the page reclaim warning are on paths that are
commonly used and I would expect to see multiple reports. I wonder
what is happening on your machine that is so unusual.

Have you run memtest on this machine for a few hours and badblocks
on the disk to ensure this is not hardware trouble?

> So is it possible that my previous BUG is triggered by slab list corruption?

Not directly, but clearly there is something very wrong.

If slub corruption reports are very common and kernel 3.0 is fine, my
strongest candidate for the corruption would be the SLUB lockless
patches. Try

git diff e4a46182e1bcc2ddacff5a35f6b52398b51f1b11..9e577e8b46ab0c38970c0f0cd7eae62e6dffddee | patch -p1 -R

They should revert cleanly with offsets.

-- 
Mel Gorman
SUSE Labs
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