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authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>2014-05-22 11:54:21 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-11 11:54:08 -0700
commit362225376da72c45248fb879178100a4aeda78f5 (patch)
treed44abfa9ad0f7c97390b2b552c6aff4156ac4f2c
parentf3a9846d7ae15244093f490f19ecb2f932494bc7 (diff)
mm/memory-failure.c: fix memory leak by race between poison and unpoison
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@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> 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@linuxfoundation.org>
-rw-r--r--mm/memory-failure.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 66586bb44c62..e346fa9d30ea 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1157,6 +1157,8 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
*/
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;
}