Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750778AbWADX4t (ORCPT ); Wed, 4 Jan 2006 18:56:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750783AbWADX4t (ORCPT ); Wed, 4 Jan 2006 18:56:49 -0500 Received: from mx1.redhat.com ([66.187.233.31]:16083 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S1750778AbWADX4s (ORCPT ); Wed, 4 Jan 2006 18:56:48 -0500 Date: Wed, 4 Jan 2006 18:56:31 -0500 From: Dave Jones To: Andrew Morton Cc: nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org Subject: Re: mm/rmap.c negative page map count BUG. Message-ID: <20060104235631.GB29634@redhat.com> Mail-Followup-To: Dave Jones , Andrew Morton , nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org References: <20060103082609.GB11738@redhat.com> <43BA630F.1020805@yahoo.com.au> <20060103135312.GB18060@redhat.com> <20060104155326.351a9c01.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060104155326.351a9c01.akpm@osdl.org> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1442 Lines: 37 On Wed, Jan 04, 2006 at 03:53:26PM -0800, Andrew Morton wrote: > Dave Jones wrote: > > > > > Can you print ->flags, ->count, ->mapping, etc instead of going BUG? > > > > I can add some instrumentation like this though, and see what turns up. > > Can we get that instrumentation into the upstream kernel please? We do > seem to be hitting rmap assertions too often for it to be dud > hardware/bodgy drivers/etc. This is what I came up with.. anything missing ? Dave --- linux-2.6.14/mm/rmap.c~ 2006-01-03 08:53:32.000000000 -0500 +++ linux-2.6.14/mm/rmap.c 2006-01-03 08:58:19.000000000 -0500 @@ -484,6 +484,13 @@ void page_remove_rmap(struct page *page) BUG_ON(PageReserved(page)); if (atomic_add_negative(-1, &page->_mapcount)) { + if (page_mapcount(page) < 0) { + printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page->_mapcount); + printk (KERN_EMERG " page->flags = %x\n", page->flags); + printk (KERN_EMERG " page->count = %x\n", page->_count); + printk (KERN_EMERG " page->mapping = %p\n", page->mapping); + } + BUG_ON(page_mapcount(page) < 0); /* * It would be tidy to reset the PageAnon mapping here, - 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/