From: Oleg Nesterov <oleg@redhat.com>
To: Pedro Alves <pedro@codesourcery.com>
Cc: archer@sourceware.org, utrace-devel@redhat.com
Subject: Re: BUG: gdb && notification packets (Was: gdbstub initial code, v12)
Date: Thu, 07 Oct 2010 23:03:00 -0000 [thread overview]
Message-ID: <20101007225922.GA18085@redhat.com> (raw)
In-Reply-To: <201010061932.31628.pedro@codesourcery.com>
On 10/06, Pedro Alves wrote:
>
> On Wednesday 06 October 2010 18:19:53, Oleg Nesterov wrote:
> >
> > Cough. Previously I was told here (on archer@sourceware.org) that
> > Hc + s/c is enough and I shouldn't worry about vCont;s/c ;)
>
> vCont was introduced because with only 'Hc', 's' and 'c', there's
> no way to distinguish "step a thread and resume all others" vs "step
> a thread and leave others stopped" (scheduler-locking, in gdb lingo).
Hmm. Not sure I understand this... gdb could issue a series of Hc+c
after s to do "step a thread and resume all others".
But this doesn't matter. Obviously vCont is better and more handy.
> Think of it as "undefined behavior". It could be made to
> error out instead, if somebody cared. Not sure how you got gdb to
> send gdbserver 's' or 'c'
I did $ gdb `which gdb` `pidof gdb` to change its behaviour ;)
> (well, unless you used
> "set remote verbose-resume-packet off", or started gdbserver
> with --disable-packet=vCont).
Ah, I'd wish I knew this before. Damn, I recall I saw these
disable_packet_xxx code in gdbserver sources, but forgot.
> > 1. Say, $vCont;s or $vCont;s:p-1.-1
> >
> > I assume, this should ignore the running threads, correct?
> > IOW, iiuc this 's' applies to all threads which we already
> > reported as stopped.
>
> Yes.
>
> >
> > 2. Say, $vCont;c:pPID.TID;s:p-1.-1
>
> This would be effectively
>
> $vCont;c:pPID.TID;s
>
> >
> > Can I assume that gdb can never send this request as
> >
> > $vCont;s:p-1.-1;c:pPID.TID ?
> >
> > If yes, then the implementation will be much simpler, I can
> > add something like gencounters to ugdb_thread/process. Otherwise
> > this needs more complications to figure out what should be done
> > with each tracee.
>
> All GDB currently sends is in gdb/remote.c:remote_vcont_resume.
> All vCont packets GDB sends today have the actions ordered
> from more specific to less specific
Great.
Pedro, thanks a lot.
Oleg.
next prev parent reply other threads:[~2010-10-07 23:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-30 18:27 gdbstub initial code, v12 Oleg Nesterov
2010-10-04 18:14 ` Oleg Nesterov
2010-10-05 17:31 ` BUG: gdb && notification packets (Was: gdbstub initial code, v12) Oleg Nesterov
2010-10-05 18:30 ` Pedro Alves
2010-10-05 18:35 ` Pedro Alves
2010-10-06 17:23 ` Oleg Nesterov
2010-10-06 18:32 ` Pedro Alves
2010-10-07 23:03 ` Oleg Nesterov [this message]
2010-10-08 0:03 ` Pedro Alves
2010-10-08 0:23 ` Oleg Nesterov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20101007225922.GA18085@redhat.com \
--to=oleg@redhat.com \
--cc=archer@sourceware.org \
--cc=pedro@codesourcery.com \
--cc=utrace-devel@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).