From: Greg Kroah-Hartman <gregkh@suse.de>
Date: Wed, 15 Sep 2010 20:54:03 +0000 (-0700)
Subject: .35 patches
X-Git-Tag: v2.6.27.54~28
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=384b4e052b686c10132d957e2a845baf905f8718;p=thirdparty%2Fkernel%2Fstable-queue.git

.35 patches
---

diff --git a/queue-2.6.35/series b/queue-2.6.35/series
index 3de3deed25b..04bd57cf720 100644
--- a/queue-2.6.35/series
+++ b/queue-2.6.35/series
@@ -59,3 +59,4 @@ alsa-hda-add-errata-initverb-sequence-for-cs42xx-codecs.patch
 alsa-hda-fix-wrong-hp-pin-detection-in-snd_hda_parse_pin_def_config.patch
 alsa-usb-audio-assume-first-control-interface-is-for-audio.patch
 alsa-hda-patch_nvhdmi.c-add-missing-codec-ids-unify-names.patch
+swap-prevent-reuse-during-hibernation.patch
diff --git a/queue-2.6.35/swap-prevent-reuse-during-hibernation.patch b/queue-2.6.35/swap-prevent-reuse-during-hibernation.patch
new file mode 100644
index 00000000000..1812f27e43c
--- /dev/null
+++ b/queue-2.6.35/swap-prevent-reuse-during-hibernation.patch
@@ -0,0 +1,74 @@
+From b73d7fcecd93dc15eaa3c45c8c587b613f6673c4 Mon Sep 17 00:00:00 2001
+From: Hugh Dickins <hughd@google.com>
+Date: Thu, 9 Sep 2010 16:38:09 -0700
+Subject: swap: prevent reuse during hibernation
+
+From: Hugh Dickins <hughd@google.com>
+
+commit b73d7fcecd93dc15eaa3c45c8c587b613f6673c4 upstream.
+
+Move the hibernation check from scan_swap_map() into try_to_free_swap():
+to catch not only the common case when hibernation's allocation itself
+triggers swap reuse, but also the less likely case when concurrent page
+reclaim (shrink_page_list) might happen to try_to_free_swap from a page.
+
+Hibernation already clears __GFP_IO from the gfp_allowed_mask, to stop
+reclaim from going to swap: check that to prevent swap reuse too.
+
+Signed-off-by: Hugh Dickins <hughd@google.com>
+Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
+Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
+Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
+Cc: Ondrej Zary <linux@rainbow-software.org>
+Cc: Andrea Gelmini <andrea.gelmini@gmail.com>
+Cc: Balbir Singh <balbir@in.ibm.com>
+Cc: Andrea Arcangeli <aarcange@redhat.com>
+Cc: Nigel Cunningham <nigel@tuxonice.net>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
+
+---
+ mm/swapfile.c |   24 ++++++++++++++++++++----
+ 1 file changed, 20 insertions(+), 4 deletions(-)
+
+--- a/mm/swapfile.c
++++ b/mm/swapfile.c
+@@ -318,10 +318,8 @@ checks:
+ 	if (offset > si->highest_bit)
+ 		scan_base = offset = si->lowest_bit;
+ 
+-	/* reuse swap entry of cache-only swap if not hibernation. */
+-	if (vm_swap_full()
+-		&& usage == SWAP_HAS_CACHE
+-		&& si->swap_map[offset] == SWAP_HAS_CACHE) {
++	/* reuse swap entry of cache-only swap if not busy. */
++	if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
+ 		int swap_was_freed;
+ 		spin_unlock(&swap_lock);
+ 		swap_was_freed = __try_to_reclaim_swap(si, offset);
+@@ -688,6 +686,24 @@ int try_to_free_swap(struct page *page)
+ 	if (page_swapcount(page))
+ 		return 0;
+ 
++	/*
++	 * Once hibernation has begun to create its image of memory,
++	 * there's a danger that one of the calls to try_to_free_swap()
++	 * - most probably a call from __try_to_reclaim_swap() while
++	 * hibernation is allocating its own swap pages for the image,
++	 * but conceivably even a call from memory reclaim - will free
++	 * the swap from a page which has already been recorded in the
++	 * image as a clean swapcache page, and then reuse its swap for
++	 * another page of the image.  On waking from hibernation, the
++	 * original page might be freed under memory pressure, then
++	 * later read back in from swap, now with the wrong data.
++	 *
++	 * Hibernation clears bits from gfp_allowed_mask to prevent
++	 * memory reclaim from writing to disk, so check that here.
++	 */
++	if (!(gfp_allowed_mask & __GFP_IO))
++		return 0;
++
+ 	delete_from_swap_cache(page);
+ 	SetPageDirty(page);
+ 	return 1;