From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists.gentoo.org ([140.105.134.102] helo=robin.gentoo.org) by nuthatch.gentoo.org with esmtp (Exim 4.54) id 1ExMgi-00078M-Fm for garchives@archives.gentoo.org; Fri, 13 Jan 2006 11:01:45 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.13.5/8.13.5) with SMTP id k0DB10ft004115; Fri, 13 Jan 2006 11:01:00 GMT Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.200]) by robin.gentoo.org (8.13.5/8.13.5) with ESMTP id k0DB0vV6019007 for ; Fri, 13 Jan 2006 11:00:58 GMT Received: by wproxy.gmail.com with SMTP id i12so562137wra for ; Fri, 13 Jan 2006 03:00:56 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=rGDZxQXpuR1ylRE77dm1pnwyxevPGJcqEemdzs6V9endAk6cbeeeyRmh+QCjVocH6rmrgnqvLftX8MM0bID9GHYiLkQYvVRtMp2DUdG1EHy+L72yM3vT5gspndvaJefN2tm/tXLOiEpN/en1M8pImgtQQlO8rmOksr2Cjb1XtjY= Received: by 10.54.128.13 with SMTP id a13mr466917wrd; Fri, 13 Jan 2006 03:00:56 -0800 (PST) Received: by 10.54.130.6 with HTTP; Fri, 13 Jan 2006 03:00:56 -0800 (PST) Message-ID: Date: Fri, 13 Jan 2006 09:00:56 -0200 From: Douglas Campos To: gentoo-embedded@lists.gentoo.org Subject: Re: [gentoo-embedded] lockups with hardened kernel In-Reply-To: <1137145814.27064.171.camel@nc> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-embedded@gentoo.org Reply-to: gentoo-embedded@lists.gentoo.org MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_14223_4917060.1137150056335" References: <1137145814.27064.171.camel@nc> X-Archives-Salt: c465b1a6-bac3-4813-8f7c-cbb860a1cf3c X-Archives-Hash: 8e47e1eec315ccc89fea6d22f7f4b1f5 ------=_Part_14223_4917060.1137150056335 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline I've found that using gcc-3.4.4-r1 made a lot of python modules going with "unresolved symbols", even when they compiled shamelessly I switched to gcc-3.3.6 and then everything went right! Just some food for thought. Cheers Douglas On 1/13/06, Natanael Copa wrote: > > On man, 2006-01-09 at 17:20 +0100, Peter S. Mazinger wrote: > > On Sat, 7 Jan 2006, Mike Frysinger wrote: > > > > > On Saturday 07 January 2006 02:30, Natanael Copa wrote: > > > > On l=F8r, 2006-01-07 at 00:44 -0500, Mike Frysinger wrote: > > > > > On Wednesday 04 January 2006 03:52, Natanael Copa wrote: > > > > > > I got a report from someone who experienced lockups when using > > > > > > gentoo-embedded built system (2.6.14-hardened-r1) > > > > > When I disabled "Configure standard kernel features (for small > > > > systems)" (gcc -Os) the problem magically went away. > > > > > > the kernel can be pretty sensitive to optimizations > > > > if kernel is built w/ gcc-3.4.4 and -Os (at least I had that for 2.4.x > > kernels) it "optimizes away" memcmp and the kernels have gotten a patch > > to overcome this, the same problem does not occur w/ gcc-3.3.x. > > > > > > So I think its a bug in gcc version 3.4.4 (Gentoo Hardened 3.4.4-r1= , > > > > ssp-3.4.4-1.0, pie-8.7.8) > > > > > > > > Makes me nervous because I have built everything with -Os. > > > > I have built everything w/ -Os and do not have trouble w/ it > > I have researched this and found out that it is not the -Os itself that > causes this, but it is something else under "Configure standard kernel > features (for small systems)". I'm not sure of exactly what but I know > at least that it is not "Optimize for size". I have turned all options > under "Configure standard kernel features (for small systems)" except > "Load all symbols for debugging/kksymoops" (including optimize for size > (-Os)) and done the netload test all night. This morning the computer > was still up. When I have an unstable kernel it hangs after an hour or > two. > > I have tried to flip the "futex support" and that did not make any > difference (anyone who know how this affects uclibc based apps btw? Do I > need futex support?) > > I think I have narrowed down the problem to one of those: > * BUG() support > * Enable full-sized data structures for core > * Enable eventpoll support > > But exactly what, I dont know. If anyone here have had any problems with > disabling one of those, I'm very interested to hear. > > Lots of bla bla here, I just thought it could be good for you guys to > know that turning off of those might make your kernel unstable, while > -Os should be ok with current gcc. > > > -- > Natanael Copa > > -- > gentoo-embedded@gentoo.org mailing list > > ------=_Part_14223_4917060.1137150056335 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline
I've found that using gcc-3.4.4-r1 made a lot of python modules going = with "unresolved symbols", even when they compiled shamelessly
 
I switched to gcc-3.3.6 and then everything went right!
 
Just some food for thought.
 
Cheers
 
Douglas

 
On 1/13/06, = Natanael Copa <mlists@tanael.or= g> wrote:
On man, 2006-01-09 at 17:20 +010= 0, Peter S. Mazinger wrote:
> On Sat, 7 Jan 2006, Mike Frysinger wrot= e:
>
> > On Saturday 07 January 2006 02:30, Natanael Copa wrot= e:
> > > On l=F8r, 2006-01-07 at 00:44 -0500, Mike Frysinger wr= ote:
> > > > On Wednesday 04 January 2006 03:52, Natanael Co= pa wrote:
> > > > > I got a report from someone who experienced lo= ckups when using
> > > > > gentoo-embedded built system (= 2.6.14-hardened-r1)

> > > When I disabled "Configure s= tandard kernel features (for small
> > > systems)" (gcc -Os) the problem magically went away= .
> >
> > the kernel can be pretty sensitive to optimizat= ions
>
> if kernel is built w/ gcc-3.4.4 and -Os (at least I ha= d that for=20 2.4.x
> kernels) it "optimizes away" memcmp and the kernels= have gotten a patch
> to overcome this, the same problem does not oc= cur w/ gcc-3.3.x.
>
> > > So I think its a bug in gcc ver= sion=20 3.4.4 (Gentoo Hardened 3.4.4-r1,
> > > ssp-3.4.4-1.0, pie-8.7.8= )
> > >
> > > Makes me nervous because I have built= everything with -Os.
>
> I have built everything w/ -Os and do= not have trouble w/ it

I have researched this and found out that it is not the -Os itself = that
causes this, but it is something else under "Configure standar= d kernel
features (for small systems)". I'm not sure of exactly wha= t but I know
at least that it is not "Optimize for size". I have turned al= l options
under "Configure standard kernel features (for small syst= ems)" except
"Load all symbols for debugging/kksymoops" (= including optimize for size
(-Os)) and done the netload test all night. This morning the computerwas still up.  When I have an unstable kernel it hangs after an= hour or
two.

I have tried to flip the "futex support" = and that did not make any
difference (anyone who know how this affects uclibc based apps btw? Do = I
need futex support?)

I think I have narrowed down the problem t= o one of those:
* BUG() support
* Enable full-sized data structures f= or core
* Enable eventpoll support

But exactly what, I dont know. If any= one here have had any problems with
disabling one of those, I'm very int= erested to hear.

Lots of bla bla here, I just thought it could be go= od for you guys to
know that turning off of those might make your kernel unstable, while-Os should be ok with current gcc.


--
Natanael Copa

= --
gentoo-embedded@gentoo.= org mailing list


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