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From: John Baldwin <jhb@freebsd.org>
To: Andriy Gapon <avg@freebsd.org>
Cc: Ryan Stone <rysto32@gmail.com>,
 "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>
Subject: Re: How to get anything useful out of kgdb?
Date: Fri, 08 Jan 2016 12:05:59 -0800
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On Saturday, October 03, 2015 12:29:30 AM Andriy Gapon wrote:
> On 02/10/2015 19:12, John Baldwin wrote:
> > On Friday, October 02, 2015 09:26:23 AM Andriy Gapon wrote:
> >> On 15/05/2015 20:57, Ryan Stone wrote:
> >>> *Sigh*,  kgdb isn't unwinding the trap frame properly.  You can try this to
> >>> figure out where it was running:
> >>
> >> I wonder, what is a reason for this?
> >> Can that be fixed in kgdb itself?
> >> It seems that usually kgdb handles trap frames just fine, but not always?
> > 
> > It should be fixable.  If this doesn't work under newer kgdb let me know and I'll
> > try to fix it.
> 
> Okay, letting you know :-)
> The backtraces from the in-tree kgdb and the newer kgdb both abort at the same
> frame (output from the newer kgdb is in my message in another kgdb related thread).

So I figured out why newer kgdb wasn't unwinding through NULL function pointer
traps yesterday.  I'm not sure if the fix will help with your case as well,
but it might be worth trying.  The changes are in
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=206044

-- 
John Baldwin