Return-Path: X-Original-To: apmail-perl-modperl-archive@www.apache.org Delivered-To: apmail-perl-modperl-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 1B66417DF4 for ; Tue, 15 Sep 2015 21:03:21 +0000 (UTC) Received: (qmail 79310 invoked by uid 500); 15 Sep 2015 21:03:20 -0000 Delivered-To: apmail-perl-modperl-archive@perl.apache.org Received: (qmail 79266 invoked by uid 500); 15 Sep 2015 21:03:20 -0000 Mailing-List: contact modperl-help@perl.apache.org; run by ezmlm Precedence: bulk list-help: list-unsubscribe: List-Post: List-Id: Delivered-To: mailing list modperl@perl.apache.org Received: (qmail 79255 invoked by uid 99); 15 Sep 2015 21:03:20 -0000 Received: from Unknown (HELO spamd1-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 15 Sep 2015 21:03:20 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd1-us-west.apache.org (ASF Mail Server at spamd1-us-west.apache.org) with ESMTP id CABC7F2CBA for ; Tue, 15 Sep 2015 21:03:19 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd1-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: 4.001 X-Spam-Level: **** X-Spam-Status: No, score=4.001 tagged_above=-999 required=6.31 tests=[HTML_MESSAGE=3, KAM_LAZY_DOMAIN_SECURITY=1, URIBL_BLOCKED=0.001] autolearn=disabled Received: from mx1-us-east.apache.org ([10.40.0.8]) by localhost (spamd1-us-west.apache.org [10.40.0.7]) (amavisd-new, port 10024) with ESMTP id bTC0wq72HGPQ for ; Tue, 15 Sep 2015 21:03:11 +0000 (UTC) Received: from mail-ob0-f176.google.com (mail-ob0-f176.google.com [209.85.214.176]) by mx1-us-east.apache.org (ASF Mail Server at mx1-us-east.apache.org) with ESMTPS id 548E04458A for ; Tue, 15 Sep 2015 21:03:11 +0000 (UTC) Received: by obbbh8 with SMTP id bh8so146105585obb.0 for ; Tue, 15 Sep 2015 14:03:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=bBwMPBk0DrZTki+J+Zzjf3NkbfsjO+eMmbkPBVbhYgw=; b=KaN8mvRwnznrjTjy2wLDxhPqtjqFG0El+ITmx5zXralAzY+9cFCMjXrZc+wMM6cWTY KhyPgx5lEmuox4N09BWE5NRP8gVjs/YOEqMTgHa5/ng9IlWBRL1aKJkS5FxbE34EF9DY doyzECzZmHJ13PtSIUDMD3vuNf4p7LdsDrbxt+6edTCQjQPyv/gN1UAZyi2cCxXgIrDb /toVlZeIV3ir+2VOuURaxAGr3Yzpgqe6PvENuz6Z709Ou/nTBw/aCP5kTwpS8F+8mxc0 CwG1BDfoQJzKmPAmlNNH0m7usgPe+TptpcOOUmu8tUv9E5tsbZL0CGZWMBL7Wu8NyCuE ol4Q== X-Gm-Message-State: ALoCoQkfDaDcHIL6UyfGzfv6q8yo3Bu57Qkh9AG21F1CAOn0dBWTBw67Ev3RwR/Ljc6i8Xyu8mQy MIME-Version: 1.0 X-Received: by 10.182.133.9 with SMTP id oy9mr17927574obb.41.1442350985600; Tue, 15 Sep 2015 14:03:05 -0700 (PDT) Received: by 10.202.198.6 with HTTP; Tue, 15 Sep 2015 14:03:05 -0700 (PDT) In-Reply-To: <55F88687.6040306@gkg.net> References: <55EBFDC0.90903@sanger.ac.uk> <55F6D959.60606@gkg.net> <55F88687.6040306@gkg.net> Date: Tue, 15 Sep 2015 17:03:05 -0400 Message-ID: Subject: Re: Random segmentation fault From: John Dunlap To: Michael Schout Cc: Steve Hay , mod_perl list Content-Type: multipart/related; boundary=e89a8ff1ccc223f334051fcf8266 --e89a8ff1ccc223f334051fcf8266 Content-Type: multipart/alternative; boundary=e89a8ff1ccc223f330051fcf8265 --e89a8ff1ccc223f330051fcf8265 Content-Type: text/plain; charset=UTF-8 First, let me thank you for your efforts! I doubt I could have come to the bottom of that. Unfortunately, I have been unable to reproduce my problem outside of a production environment and I can't risk pushing a version of perl into production that I've built myself just to test that. As unhelpful as it is, the best option for my customers, is to fall back to Debian 7(perl 5.14.2). On Tue, Sep 15, 2015 at 4:58 PM, Michael Schout wrote: > Steve, John: > > I did a bisect today against perl git, using mod_perl 2.0.9 and apache > 2.2.29 to find out where my two issues were caused. It turns out that > both of my problems, which were: > > - panic: attempt to copy freed scalar xxxx to yyyy > > and also > > - segmentation fault caused by a specific "return" statement > > Are *BOTH* caused by the following commit made to perl between 5.19.6 > and 5.19.7: > > > commit 437e3a7dac994ebace1195549170c81f474d9c20 > > Author: Matthew Horsfall > > Date: Wed Dec 11 18:28:21 2013 -0500 > > > > Optimise out PUSHMARK/RETURN if return is the last statement in a > sub. > > > > This makes: > > > > sub baz { return $cat; } > > > > Behave like: > > > > sub baz { $cat; } > > > > Which is notably faster. > ... > > I created a patch that reverses this (at least the change to op.c.. the > other parts of the patch are just new macros, and a test case), then > both of my problems are fixed. > > John: I'd be interested to know if your problem is related. If > possible, can you build perl with the attached patch applied and see if > that fixes your segfault also? > > This seems to be mod_perl specific. I have a very > straightforward/minimal test case that causes the "panic" error under > mod_perl, but the same code runs fine under the command line outside of > mod_perl. > > Regards, > Michael Schout > -- John Dunlap *CTO | Lariat * *Direct:* *john@lariat.co * *Customer Service:* 877.268.6667 support@lariat.co --e89a8ff1ccc223f330051fcf8265 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
First, let me thank you for your efforts! I doubt I could = have come to the bottom of that. Unfortunately, I have been unable to repro= duce my problem outside of a production environment and I can't risk pu= shing a version of perl into production that I've built myself just to = test that. As unhelpful as it is, the best option for my customers, is to f= all back to Debian 7(perl 5.14.2).

On Tue, Sep 15, 2015 at 4:58 PM, Michael Schout <msch= out@gkg.net> wrote:
Steve, = John:

I did a bisect today against perl git, using mod_perl 2.0.9 and apache
2.2.29 to find out where my two issues were caused.=C2=A0 It turns out that=
both of my problems, which were:

- panic: attempt to copy freed scalar xxxx to yyyy

and also

- segmentation fault caused by a specific "return" statement

Are *BOTH* caused by the following commit made to perl between 5.19.6
and 5.19.7:

> commit 437e3a7dac994ebace1195549170c81f474d9c20
> Author: Matthew Horsfall <Wol= fSage@gmail.com>
> Date:=C2=A0 =C2=A0Wed Dec 11 18:28:21 2013 -0500
>
>=C2=A0 =C2=A0 =C2=A0Optimise out PUSHMARK/RETURN if return is the last = statement in a sub.
>
>=C2=A0 =C2=A0 =C2=A0This makes:
>
>=C2=A0 =C2=A0 =C2=A0 =C2=A0sub baz { return $cat; }
>
>=C2=A0 =C2=A0 =C2=A0Behave like:
>
>=C2=A0 =C2=A0 =C2=A0 =C2=A0sub baz { $cat; }
>
>=C2=A0 =C2=A0 =C2=A0Which is notably faster.
...

I created a patch that reverses this (at least the change to op.c.. the
other parts of the patch are just new macros, and a test case), then
both of my problems are fixed.

John:=C2=A0 I'd be interested to know if your problem is related.=C2=A0= If
possible, can you build perl with the attached patch applied and see=C2=A0 = if
that fixes your segfault also?

This seems to be mod_perl specific.=C2=A0 I have a very
straightforward/minimal test case that causes the "panic" error u= nder
mod_perl, but the same code runs fine under the command line outside of
mod_perl.

Regards,
Michael Schout



--
John Dunlap
CTO |=C2=A0Lariat=C2=A0

<= span style=3D"color:rgb(153,153,153);font-family:tahoma,sans-serif;font-sty= le:normal">Direct:

Customer Service:
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