From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qa0-f48.google.com (mail-qa0-f48.google.com [209.85.216.48]) by kanga.kvack.org (Postfix) with ESMTP id C9D716B0036 for ; Sun, 4 May 2014 17:46:34 -0400 (EDT) Received: by mail-qa0-f48.google.com with SMTP id i13so1657746qae.21 for ; Sun, 04 May 2014 14:46:34 -0700 (PDT) Received: from omr-m06.mx.aol.com (omr-m06.mx.aol.com. [64.12.143.80]) by mx.google.com with ESMTPS id k47si2624089qgd.2.2014.05.04.14.46.34 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Sun, 04 May 2014 14:46:34 -0700 (PDT) Date: Sun, 4 May 2014 16:46:32 -0500 From: 502304919 Message-ID: <7B6EBC22-9E57-4702-865C-8837969E824F@aol.com> In-Reply-To: <5366A9D9.8000100@nod.at> References: <5366A9D9.8000100@nod.at> Subject: Re: [3.15rc1] BUG at mm/filemap.c:202! MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="5366b538_66334873_7f3" Sender: owner-linux-mm@kvack.org List-ID: To: Richard Weinberger Cc: "Kirill A. Shutemov" , "linux-mm@kvack.org" , Dave Jones , Andrew Morton , LKML , Sasha Levin , Johannes Weiner , Hugh Dickins --5366b538_66334873_7f3 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable I've added this to my to-do list. On May 4, 2014 at 3:58:01 PM CDT, Richa= rd Weinberger wrote:Am 04.05.2014 22:37, schrieb Hugh = Dickins:> On Sat, 3 May 2014, Richard Weinberger wrote:>> On Thu, May 1, = 2014 at 6:20 PM, Richard Weinberger>> wrote:>>> On Wed, Apr 16, 2014 at = 10:40 PM, Hugh Dickins wrote:>>>>>>>> Help=21>>>>>> Using a trinity as o= f today I'm able to trigger this bug on UML within seconds.>>> If you wan= t me to test patch, I can help.>>>>>> I'm also observing one strange fact= , I can trigger this on any kernel version.>>> So far I've managed UML to= crash on 3.0 to 3.15-rc...>>>> After digging deeper into UML's mmu and t= lb code I've found issues and>> fixed them.>>>> But I'm still facing this= issue. Although triggering the BUG=5FON() is>> not so easy as before>> I= can trigger =22BUG: Bad rss-counter ...=22 very easily.>> Now the intere= sting fact, with my UML mmu and flb fixes applied it>> happens only on ke= rnels >=3D 3.14.>> If it helps I can try to bisect it.> > Thanks a lot fo= r trying, but from other mail it looks like your> bisection got blown off= course ;(Yeah, looks like the issue I'm facing on UML is a completely di= fferentstory. Although the symptoms are identical. :-(> I expect for the = moment you'll want to concentrate on getting UML's> TLB flushing back on = track with 3.15-rc.This is what I'm currently doing. But it might take so= me timeas I'm a mm novice.> Once you have that sorted out, I wouldn't be = surprised if the same> changes turn out to fix your =22Bad rss-counter=22= s on 3.14 also.> > If not, and if you do still have time to bisect back b= etween 3.13 and> 3.14 to find where things went wrong, it will be a bit t= edious in that> you would probably have to apply> > 887843961c4b =22mm: f= ix bad rss-counter if remap=5Ffile=5Fpages raced migration=22> 7e09e738af= d2 =22mm: fix swapops.h:131 bug if remap=5Ffile=5Fpages raced migration=22= > > at each stage, to avoid those now-known bugs which trinity became rat= her> good at triggering. Perhaps other fixes needed, those the two I reme= mber.> > Please don't worry if you don't have time for this, that's under= standable.> > Or is UML so contrary that one of those commits actually br= ings on the> problem for you=3FHehe, no. I gave it a quick try, both 8878= 43961c4b and 7e09e738afd2seem to be unrelated to the issues I see.Thanks,= //richard--To unsubscribe from this list: send the line =22unsubscribe li= nux-kernel=22 inthe body of a message to majordomo=40vger.kernel.orgMore = majordomo info at http://vger.kernel.org/majordomo-info.htmlPlease read t= he =46AQ at http://www.tux.org/lkml/ --5366b538_66334873_7f3 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I've added this to my to-do list.


On May 4, 2014 at 3:58:01 PM CDT, Richard Weinberg= er <richard=40nod.at> wrote:
Am 04.05.2014 22:37, schrieb Hugh Dickins:
> On Sat, 3 = May 2014, Richard Weinberger wrote:
>> On Thu, May 1, 2014 at 6:20 P= M, Richard Weinberger
>> wrote:
>>> On Wed, Apr 16, 2014 at 10:40 PM, Hugh Dickins = wrote:
>>>>
>>>> Help=21
>>>
>>> Using a trinity as = of today I'm able to trigger this bug on UML within seconds.
>>> If = you want me to test patch, I can help.
>>>
>>> I'm also observi= ng one strange fact, I can trigger this on any kernel version.
>>> S= o far I've managed UML to crash on 3.0 to 3.15-rc...
>>
>> Afte= r digging deeper into UML's mmu and tlb code I've found issues and
>= > fixed them.
>>
>> But I'm still facing this issue. Although t= riggering the BUG=5FON() is
>> not so easy as before
>> I can t= rigger =22BUG: Bad rss-counter ...=22 very easily.
>> Now the intere= sting fact, with my UML mmu and flb fixes applied it
>> happens only= on kernels >=3D 3.14.
>> If it helps I can try to bisect it.
>=
> Thanks a lot for trying, but from other mail it looks like your<= br />> bisection got blown off course ;(

Yeah, looks like the = issue I'm facing on UML is a completely different
story. Although th= e symptoms are identical. :-(

> I expect for the moment you'll= want to concentrate on getting UML's
> TLB flushing back on track w= ith 3.15-rc.

This is what I'm currently doing. But it might ta= ke some time
as I'm a mm novice.

> Once you have that sor= ted out, I wouldn't be surprised if the same
> changes turn out to f= ix your =22Bad rss-counter=22s on 3.14 also.
>
> If not, and i= f you do still have time to bisect back between 3.13 and
> 3.14 to f= ind where things went wrong, it will be a bit tedious in that
> you = would probably have to apply
>
> 887843961c4b =22mm: fix bad r= ss-counter if remap=5Ffile=5Fpages raced migration=22
> 7e09e738afd2= =22mm: fix swapops.h:131 bug if remap=5Ffile=5Fpages raced migration=22<= br />>
> at each stage, to avoid those now-known bugs which trinity= became rather
> good at triggering. Perhaps other fixes needed, th= ose the two I remember.
>
> Please don't worry if you don't ha= ve time for this, that's understandable.
>
> Or is UML so cont= rary that one of those commits actually brings on the
> problem for = you=3F

Hehe, no. I gave it a quick try, both 887843961c4b and = 7e09e738afd2
seem to be unrelated to the issues I see.

Th= anks,
//richard
--
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Please read the =46AQ at http://www.tux.org= /lkml/
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