Re: [RFA] Don't use thread_db on corefiles

[Daniel Jacobowitz <drow at mvista dot com>]

On Thu, Dec 13, 2001 at 05:26:47PM -0800, Michael Snyder wrote:
> Daniel Jacobowitz wrote:
> > 
> > On Thu, Dec 13, 2001 at 06:56:36PM -0500, Daniel Jacobowitz wrote:
> > > Thread_db, as things stand, does not work on core files.  Is preventing
> > > it from trying, and thus crashing GDB, really such a disruptive
> > > suggestion?
> > 
> > OK, that came out a little harsher than I really wanted it.  Sorry.
> > 
> > I'd like to apply this patch and then add an entry to TODO about
> > how it "should be done".  Is that better?
> 
> I'd really like to be able to look at the problem myself.
> I have a lot invested in gdb's thread support on Linux, and
> I don't have any way to reproduce the problem you're trying
> to work around.  Could you provide a multi-threaded corefile
> with corresponding symbol file for folks to experiment with?

I'll do that.  A binary is at:
  http://www.them.org/~drow/mtc.tgz
(The core file is a 23MB sparse file because of the unmapped user
stacks.  Careful where you unpack it.)

It'll be a couple of days before I can post the patch, at best; I'm
trying to sort out stopping threads right now.

This patch is based on something posted to linux-kernel several times
over the past year by different people; most recent (if my bad memory
serves me well) was by Elan Feingold.  His patch had a fatal bug, but
still produced working core files.

> If we agree to have your workaround checked in, and then later
> decide that you've solved the problem the wrong way, then it will
> be more painful to take out your workaround and make you revisit
> the problem (after the bits have been flushed from your mental cache).  
> Better we all agree on how to solve it first.

Sure.  But I have a fixed, very imminent deadline on this; the kernel
patch took up most of the time.  I'll try to spend time on a proper
solution later.

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer