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authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>2014-05-22 11:54:21 -0700
committerShow Liu <show.liu@linaro.org>2014-06-18 12:05:17 +0800
commitc566dec26ddd82970f276370e537c009e4db5b1d (patch)
treeae814616b9cf202ba590c2f5e3c26d392794c024
parent4eb467e9356f394d59ebbbffe9d697a58907c386 (diff)
downloadlinaro-lsk-c566dec26ddd82970f276370e537c009e4db5b1d.tar.gz
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 66586bb44c6..e346fa9d30e 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;
}