Re: [Kgdb-bugreport] [PATCH][3/3] Update CVS KGDB's wrt connect / detach

[Tom Rini]

On Thu, Feb 26, 2004 at 11:05:23AM -0500, Daniel Jacobowitz wrote:

> On Thu, Feb 26, 2004 at 07:41:55AM -0700, Tom Rini wrote:
> > On Thu, Feb 26, 2004 at 01:44:49PM +0530, Amit S. Kale wrote:
> > 
> > > On Thursday 26 Feb 2004 3:23 am, Tom Rini wrote:
> > > > The following patch fixes a number of little issues here and there, and
> > > > ends up making things more robust.
> > > > - We don't need kgdb_might_be_resumed or kgdb_killed_or_detached.
> > > >   GDB attaching is GDB attaching, we haven't preserved any of the
> > > >   previous context anyhow.
> > > 
> > > If gdb is restarted, kgdb has to remove all breakpoints. Present kgdb does 
> > > that in the code this patch removes:
> > > 
> > > -		if (remcom_in_buffer[0] == 'H' && remcom_in_buffer[1] == 'c') {
> > > -			remove_all_break();
> > > -			atomic_set(&kgdb_killed_or_detached, 0);
> > > -			ok_packet(remcom_out_buffer);
> > > 
> > > If we don't remove breakpoints, they stay in kgdb without gdb not knowing it 
> > > and causes consistency problems.
> > 
> > Er, what do you mean 'restarted' ?  If gdb somehow disconnects 'detach'
> > or ^D^D, remove_all_break() gets called.  Is there another way for gdb
> > to somehow disconnect that I don't know of?
> 
> Yes.  See the disconnect command in recent GDB versions.

Ack.  Does gdb do anything to see if the rmote side will support being
left hanging?

> > > > - Don't try and look for a connection in put_packet, after we've tried
> > > >   to put a packet.  Instead, when we receive a packet, GDB has
> > > >   connected.
> > > 
> > > We have to check for gdb connection in putpacket or else following problem 
> > > occurs.
> > > 
> > > 1. kgdb console messages are to be put.
> > > 2. gdb dies
> > 
> > As in doesn't cleanly remove itself?
> 
> Seg faults, for instance.

That's what I was figuring.  Does gdbserver handle things like this (gdb
up and dying in the middle of a session, disconnecting without warning)
well?

-- 
Tom Rini
http://gate.crashing.org/~trini/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/