Received: from SOUTH-STATION-ANNEX.MIT.EDU by po7.MIT.EDU (5.61/4.7) id AA12816; Wed, 13 Dec 95 16:09:10 EST Received: from halloran-eldar.lcs.mit.edu by MIT.EDU with SMTP id AB23413; Wed, 13 Dec 95 16:09:11 EST Received: from freefall.FreeBSD.ORG by halloran-eldar.lcs.mit.edu; (5.65/1.1.8.2/19Aug95-0530PM) id AA11231; Wed, 13 Dec 1995 16:06:10 -0500 Received: from localhost (daemon@localhost) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id JAA09764 Wed, 13 Dec 1995 09:58:37 -0800 (PST) Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id JAA09637 for hackers-outgoing; Wed, 13 Dec 1995 09:57:09 -0800 (PST) Received: from cls.net (freeside.cls.de [192.129.50.1]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id JAA09632 for ; Wed, 13 Dec 1995 09:57:04 -0800 (PST) Received: by mail.cls.net (Smail3.1.29.1) from allegro.lemis.de (192.109.197.134) with smtp id ; Wed, 13 Dec 95 17:57 GMT From: grog@lemis.de (Greg Lehey) Organisation: LEMIS, Schellnhausen 2, 36325 Feldatal, Germany Phone: +49-6637-919123 Fax: +49-6637-919122 Reply-To: grog@lemis.de (Greg Lehey) Received: (grog@localhost) by allegro.lemis.de (8.6.9/8.6.9) id SAA01254 for hackers@freebsd.org; Wed, 13 Dec 1995 18:45:56 +0100 Message-Id: <199512131745.SAA01254@allegro.lemis.de> Subject: Re: samaphore remains To: terry@lambert.org (Terry Lambert) Date: Wed, 13 Dec 1995 18:45:39 +0100 (MET) In-Reply-To: <199512061915.MAA01689@phaeton.artisoft.com> from "Terry Lambert" at Dec 6, 95 12:15:29 pm X-Mailer: ELM [version 2.4 PL23] Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: owner-hackers@FreeBSD.ORG Precedence: bulk Terry Lambert writes: > >> Currently I'm using FreeBSD-R2.1.0-RELEASE on GATEWAY 2000 P5-90. >> >> I found the trouble that if a program using semaphore died >> anbormally, the semaphore which was created remains on kernel. >> I think it should be released by kernel's exit() function. >> >> Although one of the UNIX implementation calls semexit() routine from >> exit(), FreeBSD doesn't call semexit() from anywhere. >> Is there any reason for this? >> >> >> I tried to fix the exit() as follows and it seems working well. >> >> ------------- cut here --------------- >> *** kern_exit.c Tue May 30 17:05:25 1995 >> --- kern_exit.c.new Wed Dec 6 15:12:28 1995 >> *************** >> *** 130,135 **** >> --- 130,139 ---- >> */ >> fdfree(p); >> >> + #ifdef SYSVSEM >> + semexit(p); >> + #endif >> + >> /* The next two chunks should probably be moved to vmspace_exit. */ >> vm = p->p_vmspace; >> #ifdef SYSVSHM >> ------------- cut here --------------- >> >> >> -- >> Mihoko Tanaka >> > > This looks exactly right. That's a matter of definition. In System V, by default the semaphore remains beyond the death of the process. See "The Magic Garden Explained", pp 541 et seq., for an explanation which even makes this apparent nonsense make sense. The correct behaviour is to only reset the semaphore if the SEM_UNDO flag is set. I can't see any reason to ever have it not set, but maybe some broken System V software relies on it... Greg