gdb/2171: No backtrace generated on amd64

Daniel Jacobowitz
Sat Sep 16 20:28:00 GMT 2006

The following reply was made to PR gdb/2171; it has been noted by GNATS.

From: Daniel Jacobowitz <>
To: Joe Hansche <>
Subject: Re: gdb/2171: No backtrace generated on amd64
Date: Sat, 16 Sep 2006 16:26:53 -0400

 On Sat, Sep 16, 2006 at 01:15:28AM -0600, Joe Hansche wrote:
 > >This is a shared library address.  Does info shared work?  It looks
 > >like your system libraries are undebuggable, not the binary itself.
 > (gdb) info shared
 > No shared libraries loaded at this time.
 Is PHP dynamically linked?  If it is, I can only assume that either
 your kernel produces broken core dumps - this happens from time to time
 - or that something is very badly wrong with your GDB.
 Take a look with readelf -l at the php binary and the core file.
 The binary should have a DYNAMIC entry.  Do any of the LOAD entries for
 the core file cover that same address region?  If so, do they have
 non-zero values in FileSiz?
 My suspicion is that you have one of the broken kernel versions, which
 fails to dump sections if they are modified and then mprotect'd to
 Daniel Jacobowitz

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