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

Daniel Jacobowitz
2001-12-14T04:23:58Z

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.