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Date: Wed, 3 Aug 2005 12:33:00 +0100 (BST)
From: Robert Watson <rwatson@FreeBSD.org>
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To: Jeff Roberson <jeff@FreeBSD.org>
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Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject: Re: cvs commit: src/sys/alpha/alpha db_trace.c src/sys/arm/arm 
 db_trace.c src/sys/conf files src/sys/i386/i386 db_trace.c 
 src/sys/ia64/ia64 db_trace.c src/sys/kern subr_stack.c        
 src/sys/powerpc/powerpc db_trace.c src/sys/sparc64/sparc64 ...
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On Wed, 3 Aug 2005, Jeff Roberson wrote:

>  Added files:
>    sys/kern             subr_stack.c
>    sys/sys              stack.h
>  Log:
>   - Add support for saving stack traces and displaying them via printf(9)
>     and KTR.
>
>  Contributed by:         Antoine Brodin <antoine.brodin@laposte.net>
>  Concept code from:      Neal Fachan <neal@isilon.com>

This sounds really great.  I have a local /usr/src/sys/kern/kern_utrace.c 
for back-tracing user application stacks that I find quite useful -- I 
wonder if we could extend this to also work with user thread stacks?  It 
can be quite handy for determining how an application reached a 
particularly obscure kernel state.  It doesn't do the ELF magic, but does 
reach into VM to determine what object+offset backs each page pointed to 
by a return address.

Thanks,

Robert N M Watson