From owner-freebsd-hackers@freebsd.org  Thu Jul  6 23:16:39 2017
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Date: Fri, 7 Jul 2017 01:16:22 +0200
From: Joerg Sonnenberger <joerg@bec.de>
To: Conrad Meyer <cem@freebsd.org>
Cc: Marc Branchaud <marcnarc@xiplink.com>,
 "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>
Subject: Re: libexecinfo backtrace() in a signal handler
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On Thu, Jul 06, 2017 at 03:58:04PM -0700, Conrad Meyer wrote:
> Signal handlers use a special stack frame that libexecinfo is too
> simple to understand.  To get a stack from a signal handler, you might
> want to use libunwind instead.

Actually, that's not the problem. The problem is that nothing registers
the necessary unwind data.

Joerg