From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx174.postini.com [74.125.245.174]) by kanga.kvack.org (Postfix) with SMTP id C39878D0006 for ; Thu, 6 Dec 2012 13:41:35 -0500 (EST) Received: by mail-wi0-f169.google.com with SMTP id hq12so785532wib.2 for ; Thu, 06 Dec 2012 10:41:34 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20121206183259.GA591@polaris.bitmath.org> References: <20121206091744.GA1397@polaris.bitmath.org> <20121206144821.GC18547@quack.suse.cz> <20121206161934.GA17258@suse.de> <20121206175451.GC17258@suse.de> <20121206183259.GA591@polaris.bitmath.org> From: Linus Torvalds Date: Thu, 6 Dec 2012 10:41:14 -0800 Message-ID: Subject: Re: Oops in 3.7-rc8 isolate_free_pages_block() Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Henrik Rydberg Cc: Mel Gorman , Jan Kara , linux-mm , Linux Kernel Mailing List On Thu, Dec 6, 2012 at 10:32 AM, Henrik Rydberg wrote: >> >> Henrik, does that - corrected - patch (*instead* of the previous one, >> not in addition to) also fix your issue? > > Yes - I can no longer trigger the failpath, so it seems to work. Mel, > enjoy the rest of the talk. ;-) > > Generally, I am a bit surprised that noone hit this before, given that > it was quite easy to trigger. I will check 3.6 as well. Actually, looking at it some more, I think that two-liner patch had *ANOTHER* bug. Because the other line seems buggy as well. Instead of end_pfn = ALIGN(pfn + pageblock_nr_pages, pageblock_nr_pages); I think it should be end_pfn = ALIGN(pfn+1, pageblock_nr_pages); instead. ALIGN() already aligns upwards (but the "+1" is needed in case pfn is already at a pageblock_nr_pages boundary, at which point ALIGN() would have just returned that same boundary. Hmm? Mel, please confirm. And Henrik, it might be good to test that doubly-fixed patch. Because reading the patch and trying to fix bugs in it that way is *not* the same as actually verifying it ;) Linus -- 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: email@kvack.org