The patch titled
Subject: mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page()
has been removed from the -mm tree. Its filename was
mm-hwpoison-drop-lru_add_drain_all-in-__soft_offline_page.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
Subject: 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-horigu...@ah.jp.nec.com>
Cc: Andi Kleen <a...@firstfloor.org>
Cc: Tony Luck <tony.l...@intel.com>
Cc: Chen Gong <gong.c...@linux.intel.com>
Cc: <stable@vger.kernel.org> [3.11+]
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
---
mm/memory-failure.c | 2 --
1 file changed, 2 deletions(-)
diff -puN
mm/memory-failure.c~mm-hwpoison-drop-lru_add_drain_all-in-__soft_offline_page
mm/memory-failure.c
---
a/mm/memory-failure.c~mm-hwpoison-drop-lru_add_drain_all-in-__soft_offline_page
+++ a/mm/memory-failure.c
@@ -1647,8 +1647,6 @@ static int __soft_offline_page(struct pa
* 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))
_
Patches currently in -mm which might be from n-horigu...@ah.jp.nec.com are
origin.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
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