linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Linus Torvalds <torvalds@osdl.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Petr Vandrovec <vandrove@vc.cvut.cz>,
	Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@zip.com.au>,
	Roland McGrath <roland@redhat.com>
Subject: Re: [patch] Re: Problem with exiting threads under NPTL
Date: Sun, 14 Dec 2003 12:38:15 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.58.0312141228170.1478@home.osdl.org> (raw)
In-Reply-To: <Pine.LNX.4.58.0312142032310.9900@earth>



On Sun, 14 Dec 2003, Ingo Molnar wrote:
>
> the code is a bit ugly, but it's necessary - a parent can decide _after_
> starting the child that it wants to detach it. (by setting SIGCHLD to
> SIG_IGN. The testcase doesnt do this.) So the only place where we can
> detect the detached-ness of a process is in do_notify_parent().

Hmm.. What if "leader->exit_signal" was -1 already _before_ we call
"do_notify_parent()"? In that case we'd never call "do_notify_parent()"
for the leader at all, and we would also not release it outselves, the way
you've done the test.

Or is that case impossible to trigger? Looks a bit like that. But if it
_is_ impossible to trigger (ie exit_signal cannot be -1 for a thread
leader), then why does the current code test for "&& leader->exit_signal
!= -1)" at all?

That code looks fragile as hell. I think you fixed a bug and it might be
the absolutely proper fix, but I'd be happier about it if it was more
obvious what the rules are and _why_ that is the only case that matters..

		Linus

  reply	other threads:[~2003-12-14 20:38 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-12-14  5:25 Problem with exiting threads under NPTL Petr Vandrovec
2003-12-14 15:02 ` Martin Schlemmer
2003-12-14 19:38 ` [patch] " Ingo Molnar
2003-12-14 20:38   ` Linus Torvalds [this message]
2003-12-14 20:45     ` Linus Torvalds
2003-12-14 21:02       ` Ingo Molnar
2003-12-15 15:04       ` Jörn Engel
2003-12-14 21:06     ` Ingo Molnar
2003-12-14 22:10       ` Linus Torvalds
2003-12-14 22:17         ` Ingo Molnar
2003-12-14 22:32           ` Linus Torvalds
2003-12-15 23:04             ` Roland McGrath
2003-12-14 22:28         ` Ingo Molnar
2003-12-14 22:45           ` Linus Torvalds
2003-12-14 23:08             ` Ingo Molnar
2003-12-15  6:31               ` dan carpenter
2003-12-15 11:43                 ` Ingo Molnar
2003-12-15 13:07                   ` dan carpenter
2003-12-15 15:11                 ` Linus Torvalds
2003-12-15 23:15               ` Roland McGrath
2003-12-15  8:54         ` Arjan van de Ven
2003-12-15 22:55           ` Roland McGrath
2003-12-15 23:06     ` Roland McGrath

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=Pine.LNX.4.58.0312141228170.1478@home.osdl.org \
    --to=torvalds@osdl.org \
    --cc=akpm@zip.com.au \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=roland@redhat.com \
    --cc=vandrove@vc.cvut.cz \
    /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 NNTP newsgroup(s).