From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 17 Feb 2004 08:23:34 -0500 (EST) From: Rajesh Venkatasubramanian Subject: Re: [PATCH] mremap NULL pointer dereference fix In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds Cc: Andrew Morton , linux-kernel@vger.kernel.org, Linux-MM@kvack.org List-ID: > To trigger the bug you have to have _just_ the right memory usage, I > suspect. You literally have to have the destination page directory > allocation unmap the _exact_ source page (which has to be clean) for the > bug to hit. > To trigger the bug, I have to run my test program in a "while true;" loop for an hour or so. > So I suspect the oops only triggers on the machine that the trigger > program was written for. > > Your version of the patch saves a goto in the source, but results in an > extra goto in the generated assembly unless the compiler is clever enough > to notice the double test for NULL. > > Never mind, that's a micro-optimization, and your version is cleaner. > Let's go with it if Rajesh can verify that it fixes the problem for him. I will test the patch and report. Thanks, Rajesh -- 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