From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752581AbWLXTS4 (ORCPT ); Sun, 24 Dec 2006 14:18:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752532AbWLXTS4 (ORCPT ); Sun, 24 Dec 2006 14:18:56 -0500 Received: from smtp.osdl.org ([65.172.181.25]:52068 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752609AbWLXTSz (ORCPT ); Sun, 24 Dec 2006 14:18:55 -0500 Date: Sun, 24 Dec 2006 11:18:31 -0800 (PST) From: Linus Torvalds To: Andrei Popa , Peter Zijlstra , "David S. Miller" cc: Andrew Morton , Gordon Farquharson , Martin Michlmayr , Hugh Dickins , Nick Piggin , Arjan van de Ven , Linux Kernel Mailing List Subject: Re: [PATCH] mm: fix page_mkclean_one (was: 2.6.19 file content corruption on ext3) In-Reply-To: Message-ID: References: <97a0a9ac0612210117v6f8e7aefvcfb76de1db9120bb@mail.gmail.com> <97a0a9ac0612212020i6f03c3cem3094004511966e@mail.gmail.com> <20061222100004.GC10273@deprecation.cyrius.com> <20061222021714.6a83fcac.akpm@osdl.org> <1166790275.6983.4.camel@localhost> <20061222123249.GG13727@deprecation.cyrius.com> <20061222125920.GA16763@deprecation.cyrius.com> <1166793952.32117.29.camel@twins> <20061222192027.GJ4229@deprecation.cyrius.com> <97a0a9ac0612240010x33f4c51cj32d89cb5b08d4332@mail.gmail.com> <20061224005752.937493c8.akpm@osdl.org> <1166962478.7442.0.camel@localhost> <20061224043102.d152e5b4.akpm@osdl.org> <1166978752.7022.1.camel@localhost> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 24 Dec 2006, Linus Torvalds wrote: > > Peter, tell me I'm crazy, but with the new rules, the following condition > is a bug: > > - shared mapping > - writable > - not already marked dirty in the PTE Ok, so how about this diff. I'm actually feeling good about this one. It really looks like "do_no_page()" was simply buggy, and that this explains everything. Please please please test. Throw all the other patches away (with the possible exception of the "update_mmu_cache()" sanity checker, which is still interesting in case some _other_ place does this too). Don't do the "wait_on_page_writeback()" thing, because it changes timings and might hide thngs for the wrong reasons. Just apply this on top of a known failing kernel, and test. Linus --- diff --git a/mm/memory.c b/mm/memory.c index 563792f..cf429c4 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2247,21 +2249,23 @@ retry: if (pte_none(*page_table)) { flush_icache_page(vma, new_page); entry = mk_pte(new_page, vma->vm_page_prot); - if (write_access) - entry = maybe_mkwrite(pte_mkdirty(entry), vma); - set_pte_at(mm, address, page_table, entry); if (anon) { inc_mm_counter(mm, anon_rss); lru_cache_add_active(new_page); page_add_new_anon_rmap(new_page, vma, address); + if (write_access) + entry = maybe_mkwrite(pte_mkdirty(entry), vma); } else { inc_mm_counter(mm, file_rss); page_add_file_rmap(new_page); + entry = pte_wrprotect(entry); if (write_access) { dirty_page = new_page; get_page(dirty_page); + entry = maybe_mkwrite(pte_mkdirty(entry), vma); } } + set_pte_at(mm, address, page_table, entry); } else { /* One of our sibling threads was faster, back out. */ page_cache_release(new_page);