[PATCH v1 1/4] mm/memory-failure: unlock_page before put_page

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From	Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Newsgroups	linux.kernel
Subject	[PATCH v1 1/4] mm/memory-failure: unlock_page before put_page
Date	Thu, 16 Jul 2015 03:50:04 +0200
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In "just unpoisoned" path, we do put_page and then unlock_page, which is a
wrong order and causes "freeing locked page" bug. So let's fix it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
 mm/memory-failure.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git v4.2-rc2.orig/mm/memory-failure.c v4.2-rc2/mm/memory-failure.c
index c53543d89282..04d677048af7 100644
--- v4.2-rc2.orig/mm/memory-failure.c
+++ v4.2-rc2/mm/memory-failure.c
@@ -1209,9 +1209,9 @@ 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);
+		unlock_page(hpage);
 		put_page(hpage);
-		res = 0;
-		goto out;
+		return 0;
 	}
 	if (hwpoison_filter(p)) {
 		if (TestClearPageHWPoison(p))
-- 
2.4.3
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[PATCH v1 0/4] hwpoison: fixes on v4.2-rc2 Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2015-07-16 03:50 +0200
  [PATCH v1 2/4] mm/memory-failure: fix race in counting  num_poisoned_pages Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2015-07-16 03:50 +0200
  [PATCH v1 1/4] mm/memory-failure: unlock_page before put_page Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2015-07-16 03:50 +0200

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