[PATCH] mm/hwpoison: fix incorrect call put_hwpoison_page() when isolate_huge_page() return false

From: Yongkai Wu <nic.wuyk@gmail.com>
To: n-horiguchi@ah.jp.nec.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH] mm/hwpoison: fix incorrect call put_hwpoison_page() when isolate_huge_page() return false
Date: Tue, 13 Nov 2018 15:00:09 +0800	[thread overview]
Message-ID: <CAJtqMcZVQFp8U0aFqrMDD2-UGuLkWYvg3rytcCswnOT_ZMSzjQ@mail.gmail.com> (raw)

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when isolate_huge_page() return false,it won't takes a refcount of page,
if we call put_hwpoison_page() in that case,we may hit the VM_BUG_ON_PAGE!

Signed-off-by: Yongkai Wu <nic_w@163.com>
---
 mm/memory-failure.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 0cd3de3..ed09f56 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1699,12 +1699,13 @@ static int soft_offline_huge_page(struct page
*page, int flags)
  unlock_page(hpage);

  ret = isolate_huge_page(hpage, &pagelist);
- /*
- * get_any_page() and isolate_huge_page() takes a refcount each,
- * so need to drop one here.
- */
- put_hwpoison_page(hpage);
- if (!ret) {
+ if (ret) {
+        /*
+          * get_any_page() and isolate_huge_page() takes a refcount each,
+          * so need to drop one here.
+        */
+ put_hwpoison_page(hpage);
+ } else {
  pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn);
  return -EBUSY;
  }
-- 
1.8.3.1

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