Re: insight/206: SEGV in Tcl_FindCommand

[Keith Seitz <keiths at redhat dot com>]

The following reply was made to PR insight/206; it has been noted by GNATS.

From: Keith Seitz <keiths@redhat.com>
To: Lloyd J Lewins <llewins@raytheon.com>
Cc: insight-gnats@sources.redhat.com
Subject: Re: insight/206: SEGV in Tcl_FindCommand
Date: 24 Jan 2003 05:36:29 -0800

 On Thu, 2003-01-23 at 17:15, Lloyd J Lewins wrote:
 > Running the same version of insight with -nw as you suggest (on cygwin
 > platform) I do not see the problem:
 
 Hmmm. That is odd. My gdb (cvs head) locks up on me when I ask it to do
 this.
 
 > Since the SEGV is in tcl functions, I am surprised this is a problem with
 > gdb -- I thought it was only insight which used tcl/tk.
 
 Typically, insight will not crash in a platform-specific way. You're
 using c++ and there has been a lot of churn in gdb (and its
 dependencies) in this area.
 
 You're using the standard cygwin compiler, 2.95.xxx, right? I'm using
 3.2. Maybe that's why. In any case I don't think that Insight is really
 crashing in tcl/tk. I think that the stack has been corrupted.
 
 Let's try this... Run your program (in insight) to where you would add
 it to the watch window. Then open a console window and enter:
 
 (gdb) tk gdb_variable create -expr b
 var1 (<-- could be different object id)
 (gdb) tk var1 numChildren
 ??
 (gdb) tk var1 children
 ??
 
 What's the output? Do either of these cause a crash? If they do, try the
 same thing in MI:
 
 $ gdb -i=mi main
 (gdb)
 break 170
 (gdb)
 run
 (gdb)
 -var-create - * b
 ^done,name="var1",numchild="2",type="classB *"
 (gdb)
 -var-list-children var1
 ???
 
 What does this show? I'll see about updating my cygwin box (er, that
 means actually turning it on, which I haven't done in a very long time),
 but it's going to take quite some time. Please ping me on this if you
 don't hear from me for a week.
 
 Keith