Re: heavy handed exit() in latest BK

From: Linus Torvalds <torvalds@transmeta.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Anton Blanchard <anton@samba.org>, <linux-kernel@vger.kernel.org>,
	Roland McGrath <roland@redhat.com>,
	Andrew Morton <akpm@digeo.com>, <arjanv@redhat.com>
Subject: Re: heavy handed exit() in latest BK
Date: Mon, 10 Feb 2003 07:22:31 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.44.0302100720020.2127-100000@home.transmeta.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0302100951540.2724-100000@localhost.localdomain>

On Mon, 10 Feb 2003, Ingo Molnar wrote:
> 
> > Interesting. Especially as the last thing exit_notify() does (just a few
> > lines above the schedule()) is to do
> > 
> >         tsk->state = TASK_ZOMBIE;
> > 
> > and that schedule() _really_ really shouldn't return. Regardless of any
> > signal handler changes.
> 
> the proper way to avoid such scenarios (besides removing tasks from all
> waitqueues) is to remove the thread from all the PID-hashes prior setting
> it to TASK_ZOMBIE.

Not a good idea.

We still want to find zombie processes, since they show up in "ps"  
listings etc. And I don't think sending a signal to a zombie process
should return ESRCH, since it's there.

Btw, I fixed it by making all wake-up events give a mask of which states 
can be woken up. That's really what SIGCONT wanted anyway (only wake up 
stopped tasks), _and_ it's what default_wake_function() really wanted.

		Linus