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From: "Paul E. McKenney" <paulmck@us.ibm.com>
To: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>, Dipankar Sarma <dipankar@in.ibm.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC,PATCH] Use RCU to protect tasklist for unicast signals
Date: Fri, 12 Aug 2005 08:42:52 -0700	[thread overview]
Message-ID: <20050812154252.GB1297@us.ibm.com> (raw)
In-Reply-To: <42FC6305.E7A00C0A@tv-sign.ru>

On Fri, Aug 12, 2005 at 12:51:17PM +0400, Oleg Nesterov wrote:
> Paul E. McKenney wrote:
> >
> > --- linux-2.6.13-rc4-realtime-preempt-V0.7.53-01/fs/exec.c	2005-08-11 11:44:55.000000000 -0700
> > +++ linux-2.6.13-rc4-realtime-preempt-V0.7.53-01-tasklistRCU/fs/exec.c	2005-08-11 12:26:45.000000000 -0700
> > [ ... snip ... ]
> > @@ -785,11 +787,13 @@ no_thread_group:
> >  		recalc_sigpending();
> > 
> > +		oldsighand->deleted = 1;
> > +		oldsighand->successor = newsighand;
> 
> I don't think this is correct.
> 
> This ->oldsighand can be shared with another CLONE_SIGHAND
> process and will not be deleted, just unshared.
> 
> When the signal is sent to that process we must use ->oldsighand
> for locking, not the oldsighand->successor == newsighand.

Hmmm...  Sounds like I mostly managed to dig myself in deeper here.

Back to the drawing board...

						Thanx, Paul

  reply	other threads:[~2005-08-12 15:42 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-11 12:16 [RFC,PATCH] Use RCU to protect tasklist for unicast signals Oleg Nesterov
2005-08-11 15:20 ` Paul E. McKenney
2005-08-12  1:56 ` Paul E. McKenney
2005-08-12  8:51   ` Oleg Nesterov
2005-08-12 15:42     ` Paul E. McKenney [this message]
2005-08-15 17:44     ` Paul E. McKenney
2005-08-16  8:14       ` Ingo Molnar
2005-08-16 11:56       ` Oleg Nesterov
2005-08-16 17:07         ` Paul E. McKenney
2005-08-17  1:48           ` Paul E. McKenney
2005-08-17  6:35             ` Ingo Molnar
2005-08-17 14:35             ` Oleg Nesterov
2005-08-17 21:19               ` Paul E. McKenney
2005-08-18 11:48                 ` Oleg Nesterov
2005-08-19  1:29                   ` Paul E. McKenney
2005-08-19 13:27                     ` Oleg Nesterov
2005-08-19 18:34                       ` Paul E. McKenney
2005-08-18 12:24                 ` Oleg Nesterov
  -- strict thread matches above, loose matches on Subject: below --
2005-08-10 17:11 Paul E. McKenney
2005-08-11  9:56 ` Ingo Molnar
2005-08-11 14:14   ` Paul E. McKenney
2005-08-12  2:00   ` Lee Revell
2005-08-12  6:36     ` Ingo Molnar
2005-08-12 20:57       ` Paul E. McKenney
2005-08-11 17:14 ` Christoph Hellwig
2005-08-11 17:56   ` Paul E. McKenney
2005-08-11 18:00   ` Dipankar Sarma
2005-08-11 18:12     ` Dipankar Sarma

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