From owner-freebsd-hackers Sun Aug 25 00:55:42 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id AAA17991 for hackers-outgoing; Sun, 25 Aug 1996 00:55:42 -0700 (PDT) Received: from mailhub.aros.net (mailhub.aros.net [205.164.111.17]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id AAA17986 for ; Sun, 25 Aug 1996 00:55:40 -0700 (PDT) Received: from terra.aros.net (terra.aros.net [205.164.111.10]) by mailhub.aros.net (8.7.5/Unknown) with ESMTP id CAA13390; Sun, 25 Aug 1996 02:21:02 -0600 (MDT) Received: (from angio@localhost) by terra.aros.net (8.7.5/8.6.12) id BAA26732; Sun, 25 Aug 1996 01:55:37 -0600 From: Dave Andersen Message-Id: <199608250755.BAA26732@terra.aros.net> Subject: Re: kernel vm_page_alloc_contig() can indirectly cause kernel page faults To: tinguely@plains.nodak.edu (Mark Tinguely) Date: Sun, 25 Aug 1996 01:55:37 -0600 (MDT) Cc: freebsd-hackers@freebsd.org In-Reply-To: <199608250327.WAA26323@plains.nodak.edu> from "Mark Tinguely" at Aug 24, 96 10:27:02 pm X-Mailer: ELM [version 2.4 PL25 PGP2] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Is this related to an interesting kernel panic I stumbled across a while ago? It was on a -stable SNAP system from just before 2.1.5R came out. I mmapped() a relatively large block of data (about 50 megs) and, if I accessed somewhere near the end of it, it would cause a kernel panic. This was in a non-priviledged user program. The bug appears to have been corrected in 2.1.5R, however, so I didn't bother looking in to it. I don't read the commit logs too often. -Dave Andersen Lo and behold, Mark Tinguely once said: > > I reported this panic last summer when I started writing the Meteor driver. > THe work around I used wast to start the allocation starting at the > first Meg mark, at that time I speculated it was treating the low memory > and the first meg as being contiguous even though there is a memory > hole between them. Starting contiguous allocation at/after the first > meg never caused anymore panics, so I left it at that. > > --mark. > -- angio@aros.net Complete virtual hosting and business-oriented system administration Internet services. (WWW, FTP, email) http://www.aros.net/ http://www.aros.net/about/virtual "There are only two industries that refer to their customers as 'users'."