The patch below does not apply to the 3.11-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 9ab3b598d2dfbdb0153ffa7e4b1456bbff59a25d Mon Sep 17 00:00:00 2001
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Date: Thu, 12 Feb 2015 15:00:25 -0800
Subject: [PATCH] mm: hwpoison: drop lru_add_drain_all() in
__soft_offline_page()
A race condition starts to be visible in recent mmotm, where a PG_hwpoison
flag is set on a migration source page *before* it's back in buddy page
poo= l.
This is problematic because no page flag is supposed to be set when
freeing (see __free_one_page().) So the user-visible effect of this race
is that it could trigger the BUG_ON() when soft-offlining is called.
The root cause is that we call lru_add_drain_all() to make sure that the
page is in buddy, but that doesn't work because this function just
schedule= s a work item and doesn't wait its completion.
drain_all_pages() does drainin= g directly, so simply dropping
lru_add_drain_all() solves this problem.
Fixes: f15bdfa802bf ("mm/memory-failure.c: fix memory leak in successful soft offlining")
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Chen Gong <gong.chen@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [3.11+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 1a735fad2a13..d487f8dc6d39 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1647,8 +1647,6 @@ static int __soft_offline_page(struct page *page, int flags)
* setting PG_hwpoison.
*/
if (!is_free_buddy_page(page))
- lru_add_drain_all();
- if (!is_free_buddy_page(page))
drain_all_pages(page_zone(page));
SetPageHWPoison(page);
if (!is_free_buddy_page(page))
--
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