Date:	Fri, 5 Aug 2011 20:30:44 +0800
From:	Xiaotian Feng <xtfeng@...il.com>
To:	Mel Gorman <mgorman@...e.de>
Cc:	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Pekka Enberg <penberg@...nel.org>,
	Christoph Lameter <cl@...ux.com>
Subject: Re: kernel BUG at mm/vmscan.c:1114

On Fri, Aug 5, 2011 at 8:09 PM, Xiaotian Feng <xtfeng@...il.com> wrote:
> On Fri, Aug 5, 2011 at 5:19 PM, Mel Gorman <mgorman@...e.de> wrote:
>> (Adding patch author to cc)
>>
>> On Fri, Aug 05, 2011 at 04:42:43PM +0800, Xiaotian Feng wrote:
>>> On Thu, Aug 4, 2011 at 11:54 AM, Xiaotian Feng <xtfeng@...il.com> wrote:
>>> > On Wed, Aug 3, 2011 at 4:54 PM, Mel Gorman <mgorman@...e.de> wrote:
>>> >> 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@...ux-foundation.org> wrote:
>>> >>> > On Tue, 2 Aug 2011 15:09:57 +0800 Xiaotian Feng <xtfeng@...il.com> 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
>>> >>>
>>> >>
>>> >
>>> > I'm hitting this again today, when I'm trying to rebuild my kernel....
>>> > Looking it a bit
>>> >
>>> >  list_del corruption. next->prev should be ffffea0000e069a0, but was
>>> > ffff880100216c78
>>> >
>>> > I find something interesting from my syslog:
>>> >
>>> >  PERCPU: Embedded 28 pages/cpu @ffff880100200000 s83456 r8192 d23040 u262144
>>> >
>>> >> 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
>>> >>
>>> >
>>>
>>> Here's a update for the results:
>>>
>>> 3.0.0-rc7: running for hours without a crash
>>> upstream kernel: list corruption happened while building kernel within
>>> 10 mins (I'm running some app chrome/firefox/thunderbird/... as well)
>>> upstream kernel with above revert: running for hours without a crash
>>>
>>> Trying to bisect but rebuild is slow ....
>>>
>>
>> If you have not done so already, I strongly suggest your bisection
>> starts within that range of patches to isolate which one is at fault.
>> It'll cut down on the number of builds you need to do. Thanks for
>> testing.
>>
>
> This is interesting, I just change as following:
>
> diff --git a/mm/slub.c b/mm/slub.c
> index eb5a8f9..616b78e 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2104,8 +2104,9 @@ static void *__slab_alloc(struct kmem_cache *s,
> gfp_t gfpflags, int node,
>                        "__slab_alloc"));
>
>        if (unlikely(!object)) {
> -               c->page = NULL;
> +               //c->page = NULL;
>                stat(s, DEACTIVATE_BYPASS);
> +               deactivate_slab(s, c);
>                goto new_slab;
>        }
>
> Then my system doesn't print any list corruption warnings and my build
> success then. So this means revert of 03e404af2 could cure this.
> I'll do more test next week to see if the list corruption still exist, thanks.
>

Sorry, please ignore it... My system corrupted before I went to leave ....

>
>
>> --
>> Mel Gorman
>> SUSE Labs
>>
>
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