From owner-freebsd-hackers Sun Sep 14 08:28:01 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id IAA14153 for hackers-outgoing; Sun, 14 Sep 1997 08:28:01 -0700 (PDT) Received: from dyson.iquest.net (dyson.iquest.net [198.70.144.127]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id IAA14131 for ; Sun, 14 Sep 1997 08:27:58 -0700 (PDT) Received: (from root@localhost) by dyson.iquest.net (8.8.6/8.8.5) id KAA00185; Sun, 14 Sep 1997 10:27:52 -0500 (EST) From: "John S. Dyson" Message-Id: <199709141527.KAA00185@dyson.iquest.net> Subject: Re: What is wrong with this snipet? In-Reply-To: <199709141011.DAA01459@lestat.nas.nasa.gov> from Jason Thorpe at "Sep 14, 97 03:11:10 am" To: thorpej@nas.nasa.gov Date: Sun, 14 Sep 1997 10:27:52 -0500 (EST) Cc: freebsd-hackers@FreeBSD.ORG Reply-To: dyson@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL31 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Jason Thorpe said: > On Sat, 13 Sep 1997 16:34:42 -0700 (PDT) > Simon Shapiro wrote: > > > Why would the following segfault on 6 of the 10 iterations? > > In the FreeBSD implementation of RFMEM (which does not match Plan 9's), > the child gets the same stack as the parent. If you "return" in the child, > someone's stack gets munched. > We are going to be supporting a super efficient threads scheme that uses the RFMEM capability. Sample code to use RFMEM is available upon request. It is already being used in commercial multi-threaded applications, but isn't ready for inclusion in FreeBSD (yet), due to a lack of more general userland support. RFMEM supports full address space sharing in FreeBSD, and it is a bug otherwise (whomever implemented it first.) -- John dyson@freebsd.org jdyson@nc.com