Subject: Re: SMP problems in fork()?
To: David Laight <david@l8s.co.uk>
From: Antti Kantee <pooka@cs.hut.fi>
List: tech-kern
Date: 12/08/2002 23:36:22
On Sun Dec 08 2002 at 21:19:29 +0000, David Laight wrote:
> Consider also the case of fork with both FORK_PPWAIT and FORK_NOWAIT
> set (ie vfork with the parent set to initproc).
> 
> The process priorities could be such that:
> 	if (flags & FORK_PPWAIT)
> 		while (p2->p_flag & P_PPWAIT)
> 			tsleep(p1, PWAIT, "ppwait", 0);
> 
> accesses p2->p_flag after the child has been reaped - even on
> a single cpu system.

vfork with nowait doesn't make much sense. Besides, there's nothing that
calls fork1() with both set, and I can't imagine why there ever would be.

-- 
Antti Kantee <pooka@iki.fi>                     Of course he runs NetBSD
http://www.iki.fi/pooka/                          http://www.NetBSD.org/
                 "connoisseurs do not chill their malts."