linux-kernel - [PATCH v2 1/6] mm, hwpoison: fix page refcnt leaking in try_memory_failure

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Date:   Tue, 23 Aug 2022 11:23:41 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>, <naoya.horiguchi@....com>
CC:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <linmiaohe@...wei.com>
Subject: [PATCH v2 1/6] mm, hwpoison: fix page refcnt leaking in try_memory_failure_hugetlb()

When hwpoison_filter() refuses to hwpoison a hugetlb page, the refcnt of
the page would have been incremented if res == 1. Using put_page() to fix
the refcnt leaking in this case.

Fixes: 405ce051236c ("mm/hwpoison: fix race between hugetlb free/demotion and memory_failure_hugetlb()")
Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@....com>
---
 mm/memory-failure.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 5b368124956d..9d1ebfef04ee 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1860,8 +1860,10 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb
 
 	if (hwpoison_filter(p)) {
 		hugetlb_clear_page_hwpoison(head);
-		res = -EOPNOTSUPP;
-		goto out;
+		unlock_page(head);
+		if (res == 1)
+			put_page(head);
+		return -EOPNOTSUPP;
 	}
 
 	/*
-- 
2.23.0