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Message-ID: <78c6bd860804132325r117c8ea1x2c631202a3b39644@mail.gmail.com>
Date: Mon, 14 Apr 2008 02:25:39 -0400
From: "Michael B Allen" <ioplex@gmail.com>
To: dev@httpd.apache.org
Subject: Re: FPE in linux loader on custom PHP extension
In-Reply-To: <78c6bd860804101352xc4fa9fej929712240316a6ed@mail.gmail.com>
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References: <78c6bd860804101352xc4fa9fej929712240316a6ed@mail.gmail.com>

On 4/10/08, Michael B Allen <ioplex@gmail.com> wrote:
> Sorry this is a bit OT but I'm not sure what to do next and would
>  really appreciate some ideas.
>
>  One of my clients is seeing an FPE in ld-linux-x86-64.so when loading
>  a custom PHP extension. The backtrace is inlined below.
>
>  At least I assume it's blowing up loading my extension - with my
>  extension disabled, everything loads and runs ok.
>
>  # gdb /usr/sbin/httpd2-prefork
>  GNU gdb 6.6
>  Copyright (C) 2006 Free Software Foundation, Inc.
>  GDB is free software, covered by the GNU General Public License, and you are
>  welcome to change it and/or distribute copies of it under certain
>  conditions.
>  Type "show copying" to see the conditions.
>  There is absolutely no warranty for GDB.  Type "show warranty" for details.
>  This GDB was configured as "x86_64-suse-linux"...
>  (no debugging symbols found)
>  Using host libthread_db library "/lib64/libthread_db.so.1".
>  (gdb) run -X
>  Starting program: /usr/sbin/httpd2-prefork -X
>  (no debugging symbols found)
>  (no debugging symbols found)
>  (no debugging symbols found)
>
>  [snipped]
>
>  [Thread debugging using libthread_db enabled]
>  [New Thread 47783686579872 (LWP 11366)]
>  (no debugging symbols found)
>  (no debugging symbols found)
>  (no debugging symbols found)
>
>  [snipped]
>
>  Program received signal SIGFPE, Arithmetic exception.
>  [Switching to Thread 47783686579872 (LWP 11366)]
>  0x00002b758030468f in do_lookup_x () from /lib64/ld-linux-x86-64.so.2
>  (gdb) bt
>  #0  0x00002b758030468f in do_lookup_x () from /lib64/ld-linux-x86-64.so.2

This turned out to be a backward compatibility problem with .hash vs
newer .hash.gnu sections in the libs. Google on "SIGFPE do_lookup_x"
for details.

Signing off,
Mike

-- 
Michael B Allen
PHP Active Directory SPNEGO SSO
http://www.ioplex.com/