Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261954AbVA0C4j (ORCPT ); Wed, 26 Jan 2005 21:56:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262447AbVAZXRE (ORCPT ); Wed, 26 Jan 2005 18:17:04 -0500 Received: from zcars04f.nortelnetworks.com ([47.129.242.57]:34733 "EHLO zcars04f.nortelnetworks.com") by vger.kernel.org with ESMTP id S262450AbVAZRfR (ORCPT ); Wed, 26 Jan 2005 12:35:17 -0500 Message-ID: <41F7D4B0.7070401@nortelnetworks.com> Date: Wed, 26 Jan 2005 11:34:40 -0600 X-Sybari-Space: 00000000 00000000 00000000 00000000 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040115 X-Accept-Language: en-us, en MIME-Version: 1.0 To: linux-os@analogic.com CC: Rik van Riel , Andrew Morton , linux-kernel@vger.kernel.org, James Antill , Bryn Reeves Subject: Re: don't let mmap allocate down to zero References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 908 Lines: 25 linux-os wrote: > Does this mean that we can't mmap the screen regen buffer at > 0x000b8000 anymore? > > How do I look at the real-mode interrupt table starting at > offset 0? You know that the return value of mmap is to be > checked for MAP_FAILED, not for NULL, don't you? Can't you still map those physical addresses to other virtual addresses? > What 'C' standard do you refer to? Seg-faults on null pointers > have nothing to do with the 'C' standard and everything to > do with the platform. I believe the ISO/IEC 9899:1999 C Standard explicitly states that dereferencing a null pointer with the unary * operator results in undefined behavior. Chris - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/