Patch "mm: avoid reinserting isolated balloon pages into LRU lists" has been added to the 3.10-stable tree

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This is a note to let you know that I've just added the patch titled

    mm: avoid reinserting isolated balloon pages into LRU lists

to the 3.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mm-avoid-reinserting-isolated-balloon-pages-into-lru-lists.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 117aad1e9e4d97448d1df3f84b08bd65811e6d6a Mon Sep 17 00:00:00 2001
From: Rafael Aquini <aquini@xxxxxxxxxx>
Date: Mon, 30 Sep 2013 13:45:16 -0700
Subject: mm: avoid reinserting isolated balloon pages into LRU lists

From: Rafael Aquini <aquini@xxxxxxxxxx>

commit 117aad1e9e4d97448d1df3f84b08bd65811e6d6a upstream.

Isolated balloon pages can wrongly end up in LRU lists when
migrate_pages() finishes its round without draining all the isolated
page list.

The same issue can happen when reclaim_clean_pages_from_list() tries to
reclaim pages from an isolated page list, before migration, in the CMA
path.  Such balloon page leak opens a race window against LRU lists
shrinkers that leads us to the following kernel panic:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
  IP: [<ffffffff810c2625>] shrink_page_list+0x24e/0x897
  PGD 3cda2067 PUD 3d713067 PMD 0
  Oops: 0000 [#1] SMP
  CPU: 0 PID: 340 Comm: kswapd0 Not tainted 3.12.0-rc1-22626-g4367597 #87
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  RIP: shrink_page_list+0x24e/0x897
  RSP: 0000:ffff88003da499b8  EFLAGS: 00010286
  RAX: 0000000000000000 RBX: ffff88003e82bd60 RCX: 00000000000657d5
  RDX: 0000000000000000 RSI: 000000000000031f RDI: ffff88003e82bd40
  RBP: ffff88003da49ab0 R08: 0000000000000001 R09: 0000000081121a45
  R10: ffffffff81121a45 R11: ffff88003c4a9a28 R12: ffff88003e82bd40
  R13: ffff88003da0e800 R14: 0000000000000001 R15: ffff88003da49d58
  FS:  0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000067d9000 CR3: 000000003ace5000 CR4: 00000000000407b0
  Call Trace:
    shrink_inactive_list+0x240/0x3de
    shrink_lruvec+0x3e0/0x566
    __shrink_zone+0x94/0x178
    shrink_zone+0x3a/0x82
    balance_pgdat+0x32a/0x4c2
    kswapd+0x2f0/0x372
    kthread+0xa2/0xaa
    ret_from_fork+0x7c/0xb0
  Code: 80 7d 8f 01 48 83 95 68 ff ff ff 00 4c 89 e7 e8 5a 7b 00 00 48 85 c0 49 89 c5 75 08 80 7d 8f 00 74 3e eb 31 48 8b 80 18 01 00 00 <48> 8b 74 0d 48 8b 78 30 be 02 00 00 00 ff d2 eb
  RIP  [<ffffffff810c2625>] shrink_page_list+0x24e/0x897
   RSP <ffff88003da499b8>
  CR2: 0000000000000028
  ---[ end trace 703d2451af6ffbfd ]---
  Kernel panic - not syncing: Fatal exception

This patch fixes the issue, by assuring the proper tests are made at
putback_movable_pages() & reclaim_clean_pages_from_list() to avoid
isolated balloon pages being wrongly reinserted in LRU lists.

[akpm@xxxxxxxxxxxxxxxxxxxx: clarify awkward comment text]
Signed-off-by: Rafael Aquini <aquini@xxxxxxxxxx>
Reported-by: Luiz Capitulino <lcapitulino@xxxxxxxxxx>
Tested-by: Luiz Capitulino <lcapitulino@xxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 include/linux/balloon_compaction.h |   25 +++++++++++++++++++++++++
 mm/migrate.c                       |    2 +-
 mm/vmscan.c                        |    4 +++-
 3 files changed, 29 insertions(+), 2 deletions(-)

--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -159,6 +159,26 @@ static inline bool balloon_page_movable(
 }
 
 /*
+ * isolated_balloon_page - identify an isolated balloon page on private
+ *			   compaction/migration page lists.
+ *
+ * After a compaction thread isolates a balloon page for migration, it raises
+ * the page refcount to prevent concurrent compaction threads from re-isolating
+ * the same page. For that reason putback_movable_pages(), or other routines
+ * that need to identify isolated balloon pages on private pagelists, cannot
+ * rely on balloon_page_movable() to accomplish the task.
+ */
+static inline bool isolated_balloon_page(struct page *page)
+{
+	/* Already isolated balloon pages, by default, have a raised refcount */
+	if (page_flags_cleared(page) && !page_mapped(page) &&
+	    page_count(page) >= 2)
+		return __is_movable_balloon_page(page);
+
+	return false;
+}
+
+/*
  * balloon_page_insert - insert a page into the balloon's page list and make
  *		         the page->mapping assignment accordingly.
  * @page    : page to be assigned as a 'balloon page'
@@ -242,6 +262,11 @@ static inline bool balloon_page_movable(
 {
 	return false;
 }
+
+static inline bool isolated_balloon_page(struct page *page)
+{
+	return false;
+}
 
 static inline bool balloon_page_isolate(struct page *page)
 {
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -103,7 +103,7 @@ void putback_movable_pages(struct list_h
 		list_del(&page->lru);
 		dec_zone_page_state(page, NR_ISOLATED_ANON +
 				page_is_file_cache(page));
-		if (unlikely(balloon_page_movable(page)))
+		if (unlikely(isolated_balloon_page(page)))
 			balloon_page_putback(page);
 		else
 			putback_lru_page(page);
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -48,6 +48,7 @@
 #include <asm/div64.h>
 
 #include <linux/swapops.h>
+#include <linux/balloon_compaction.h>
 
 #include "internal.h"
 
@@ -978,7 +979,8 @@ unsigned long reclaim_clean_pages_from_l
 	LIST_HEAD(clean_pages);
 
 	list_for_each_entry_safe(page, next, page_list, lru) {
-		if (page_is_file_cache(page) && !PageDirty(page)) {
+		if (page_is_file_cache(page) && !PageDirty(page) &&
+		    !isolated_balloon_page(page)) {
 			ClearPageActive(page);
 			list_move(&page->lru, &clean_pages);
 		}


Patches currently in stable-queue which might be from aquini@xxxxxxxxxx are

queue-3.10/mm-avoid-reinserting-isolated-balloon-pages-into-lru-lists.patch
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