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From: Mike Mason <mmlnx@us.ibm.com>
To: Martin Hunt <hunt@redhat.com>
Cc: systemtap@sources.redhat.com
Subject: Re: stack trace changes
Date: Thu, 12 Oct 2006 22:19:00 -0000	[thread overview]
Message-ID: <452EBF4A.8000500@us.ibm.com> (raw)
In-Reply-To: <1160679497.4762.11.camel@dragon>

Thanks for working on this.  See comments below...

Martin Hunt wrote:
> I've checked in a rewrite of the stack trace code.  I rewrote i386 and
> x86_64 only. ppc64 and ia64 should still work as before, unless I made
> any errors while reorganizing the code.

I'll test on ppc64 after the build error is fixed in the ppc64 runtine
(see bug 3051).

> 
> In 2.6.18 there is code to use DWARF to accurately unwind the stacks.
> The new code uses this if available, otherwise it falls back to the
> inaccurate unwinder.  Some situations like kretprobe trampolines confuse
> the unwinder and it does what it can accurately then uses the inaccurate
> unwinder. In all cases, it now says when the trace in not accurate.

I tested print_backtrace on 2.6.17-1.2187_FC5 on x86_64. I now see a 
single line(as before) followed by "Inexact backtrace:" and then 
nothing. Is there no way to get additional stack info on x86_64 
kernels earlier than 2.6.18?  Just want to know what to expect.

I tested on 2.6.18 as well and it appears to work as you described.

Thanks again for your efforts.

- Mike

  reply	other threads:[~2006-10-12 22:19 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-12 18:58 Martin Hunt
2006-10-12 22:19 ` Mike Mason [this message]
2006-10-13 14:38   ` Martin Hunt

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