Memory corruption during hibernation since 2.6.31
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From: Hugh Dickins on 30 Jul 2010 14:20 On Fri, Jul 30, 2010 at 3:43 AM, KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: > plz wait until the next week..I found I can't post today ;( > > Maybe trying my quick hack patch (posted) will be enough small for > backporting etc. Absolutely. I didn't intend my broader anxieties to distract from your immediate scan_swap_map() fix. If Ondrej finds that it does in fact fix the corruption he's been seeing since 2.6.31, then I'd like your fix to go straight to Linus for 2.6.35: once swap is 50% full, your case is rather too likely to occur; whereas I'm worrying about correctness in unlikely hypothetical circumstances. But please do credit Ondrej, and make clear that you're fixing an observed corrution; and feel free to add my Acked-by: Hugh Dickins <hughd(a)google.com> Hugh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andrea Gelmini on 3 Aug 2010 07:00 2010/7/29 KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com>: > Considering possible cases...and here is a patch. > but I'm not fully sure. Could you clarify ? I'm using this patch (with the one for ksm.c by Arcangeli) since the publishing. It seems all works pretty well, with TuxOnIce also. Never had the need to reboot the system. Thanks a lot, Andrea -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: KAMEZAWA Hiroyuki on 3 Aug 2010 19:50 On Tue, 3 Aug 2010 12:50:43 +0200 Andrea Gelmini <andrea.gelmini(a)gmail.com> wrote: > 2010/7/29 KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com>: > > Considering possible cases...and here is a patch. > > but I'm not fully sure. Could you clarify ? > > I'm using this patch (with the one for ksm.c by Arcangeli) since the publishing. > It seems all works pretty well, with TuxOnIce also. > > Never had the need to reboot the system. > Good, thank you for reporting ! I'd like to add your Tested-by: Thanks, -Kame > Thanks a lot, > Andrea > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andrea Gelmini on 5 Aug 2010 07:50 2010/8/4 KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com>: > Good, thank you for reporting ! > I'd like to add your Tested-by: No prob. Thanks a lot for your work, Andrea -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Ondrej Zary on 5 Aug 2010 08:50
On Thursday 29 July 2010 07:24:29 KAMEZAWA Hiroyuki wrote: > On Thu, 29 Jul 2010 14:23:33 +0900 (JST) > > KOSAKI Motohiro <kosaki.motohiro(a)jp.fujitsu.com> wrote: > > Can you please add explicit commenting in the code? > > How about this ? > == > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com> > > 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. 6 days with no crash - so the patch seems to work. > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com> > --- > 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); > -- Ondrej Zary -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |