This is a note to let you know that I've just added the patch titled
mm/memory-failure.c: fix memory leak by race between poison and unpoison
to the 3.14-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-memory-failure.c-fix-memory-leak-by-race-between-poison-and-unpoison.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3e030ecc0fc7de10fd0da10c1c19939872a31717 Mon Sep 17 00:00:00 2001
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Date: Thu, 22 May 2014 11:54:21 -0700
Subject: mm/memory-failure.c: fix memory leak by race between poison and unpoison
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
commit 3e030ecc0fc7de10fd0da10c1c19939872a31717 upstream.
When a memory error happens on an in-use page or (free and in-use)
hugepage, the victim page is isolated with its refcount set to one.
When you try to unpoison it later, unpoison_memory() calls put_page()
for it twice in order to bring the page back to free page pool (buddy or
free hugepage list). However, if another memory error occurs on the
page which we are unpoisoning, memory_failure() returns without
releasing the refcount which was incremented in the same call at first,
which results in memory leak and unconsistent num_poisoned_pages
statistics. This patch fixes it.
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 2 ++
1 file changed, 2 insertions(+)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1157,6 +1157,8 @@ int memory_failure(unsigned long pfn, in
*/
if (!PageHWPoison(p)) {
printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn);
+ atomic_long_sub(nr_pages, &num_poisoned_pages);
+ put_page(hpage);
res = 0;
goto out;
}
Patches currently in stable-queue which might be from n-horiguchi@xxxxxxxxxxxxx are
queue-3.14/mm-memory-failure.c-fix-memory-leak-by-race-between-poison-and-unpoison.patch
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