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Re: gdb/331: watch is finicky about giving a hardware watchpoint
- From: Dru Nelson <dru at redwoodsoft dot com>
- To: nobody at sources dot redhat dot com
- Cc: gdb-prs at sources dot redhat dot com,
- Date: 2 Feb 2002 23:18:01 -0000
- Subject: Re: gdb/331: watch is finicky about giving a hardware watchpoint
- Reply-to: Dru Nelson <dru at redwoodsoft dot com>
The following reply was made to PR gdb/331; it has been noted by GNATS.
From: Dru Nelson <dru@redwoodsoft.com>
To: Daniel Jacobowitz <drow@mvista.com>
Cc: dru-gdb@redwoodsoft.com, <gdb-gnats@sources.redhat.com>
Subject: Re: gdb/331: watch is finicky about giving a hardware watchpoint
Date: Sat, 2 Feb 2002 15:17:26 -0800 (PST)
One last email.
I'll work on that patch tonight. Shouldn't be too hard.
Thanks,
Dru Nelson
San Mateo, California
On Sat, 2 Feb 2002, Daniel Jacobowitz wrote:
> On Sat, Feb 02, 2002 at 10:41:42PM -0000, dru-gdb@redwoodsoft.com wrote:
> >
> > >Number: 331
> > >Category: gdb
> > >Synopsis: watch is finicky about giving a hardware watchpoint
> > >Confidential: no
> > >Severity: serious
> > >Priority: medium
> > >Responsible: unassigned
> > >State: open
> > >Class: sw-bug
> > >Submitter-Id: net
> > >Arrival-Date: Sat Feb 02 14:48:01 PST 2002
> > >Closed-Date:
> > >Last-Modified:
> > >Originator: Dru
> > >Release: gdb 5.1.1
> > >Organization:
> > >Environment:
> > linux 2.2.16 (patched with jcrown debug register patches)
> > x86
> > >Description:
> > When I set a watch to a named variable, gdb will create a
> > 'hardware watchpoint'. However if I issue:
> > 'watch 0x81d79a8' gdb creates a software watchpoint.
> > This is annoying since I'm debugging after a segmentation
> > violation and I need to re-run the program to see who is
> > writing to that memory.
> >
> > Why isn't this a valid expression to create a hardware
> > watchpoint that doesn't rely on variable scope?
>
> That's watching the value of '0x81d79a8'. A constant. You want:
> watch *(int *)0x81d79a8
>
> which should create a hardware watchpoint.
>
> I agree we should warn about this.
>
> --
> Daniel Jacobowitz Carnegie Mellon University
> MontaVista Software Debian GNU/Linux Developer
>