Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752202Ab0G2Rdf (ORCPT ); Thu, 29 Jul 2010 13:33:35 -0400 Received: from mail1-out1.atlantis.sk ([80.94.52.55]:53831 "EHLO mail.atlantis.sk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751173Ab0G2Rdd (ORCPT ); Thu, 29 Jul 2010 13:33:33 -0400 From: Ondrej Zary To: KAMEZAWA Hiroyuki Subject: Re: Memory corruption during hibernation since 2.6.31 Date: Thu, 29 Jul 2010 19:33:18 +0200 User-Agent: KMail/1.9.10 Cc: KOSAKI Motohiro , "Rafael J. Wysocki" , Kernel development list , Andrew Morton , Balbir Singh References: <201007282334.08063.rjw@sisk.pl> <20100729142245.4AA5.A69D9226@jp.fujitsu.com> <20100729142429.58b49dce.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20100729142429.58b49dce.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201007291933.21568.linux@rainbow-software.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2860 Lines: 75 On Thursday 29 July 2010 07:24:29 KAMEZAWA Hiroyuki wrote: > On Thu, 29 Jul 2010 14:23:33 +0900 (JST) > > KOSAKI Motohiro wrote: > > Can you please add explicit commenting in the code? > > How about this ? > == > From: KAMEZAWA Hiroyuki > > At hibernation, all pages-should-be-saved are written into a image (here, > swap). Then, swap_map[], memmap etcs are also saved into disks. > > But, swap allocation happens one by one. So, the final image of swap_map[] > is different from saved one and the commit > c9e444103b5e7a5a3519f9913f59767f92e33baf changes page's state while > assiging swap. Because memory can be modified in hibernation is only > not-to-be-save memory. it's a breakage. > > This patch fixes it by disabling swap entry reuse at hibernation. Thanks for the patch, I'm going to test it for a few days. It didn't compile with 2.6.32 (because of missing "usage" parameter) so I tried 2.6.35-rc6 only to find that there's regression since 2.6.34 that causes console font corruption with matroxfb. Almost every new kernel means new regressions on this machine. Looks like something is wrong with the development process... So at least the patch compiles with 2.6.33 where the console works - so that's going to be tested. > Signed-off-by: KAMEZAWA Hiroyuki > --- > mm/swapfile.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > Index: linux-2.6.34.org/mm/swapfile.c > =================================================================== > --- linux-2.6.34.org.orig/mm/swapfile.c > +++ linux-2.6.34.org/mm/swapfile.c > @@ -315,8 +315,15 @@ checks: > if (offset > si->highest_bit) > scan_base = offset = si->lowest_bit; > > - /* reuse swap entry of cache-only swap if not busy. */ > - if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { > + /* > + * reuse swap entry of cache-only swap if not busy && > + * when we're called via pageout(). At hibernation, swap-reuse > + * is harmful because it changes memory status...which may > + * be saved already. > + */ > + if (vm_swap_full() > + && usage == SWAP_HAS_CACHE > + && si->swap_map[offset] == SWAP_HAS_CACHE) { > int swap_was_freed; > spin_unlock(&swap_lock); > swap_was_freed = __try_to_reclaim_swap(si, offset); > > -- > 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/ -- Ondrej Zary -- 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/