From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH] prevent NULL mmap in topdown model References: <20050519064657.GH23013@shell0.pdx.osdl.net> <1116490511.6027.25.camel@laptopd505.fenrus.org> In-Reply-To: <1116490511.6027.25.camel@laptopd505.fenrus.org> From: Greg Stark Date: 29 May 2005 17:16:33 -0400 Message-ID: <87u0klybpq.fsf@stark.xeocode.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org Return-Path: To: Arjan van de Ven Cc: Chris Wright , Linus Torvalds , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Arjan van de Ven writes: > On Wed, 2005-05-18 at 23:46 -0700, Chris Wright wrote: > > sure. Making it *impossible* to mmap that page is bad. People should be > able to do that if they really want to, just doing it if they don't ask > for it is bad. > > There are plenty of reasons people may want that page mmaped, one of > them being that the compiler can then do more speculative loads around > null pointer checks. Not saying it's a brilliant idea always, but making > such things impossible makes no sense. More realistically, iirc either Wine or dosemu, i forget which, actually has to map page 0 to work properly. -- greg -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org