linux-kernel - [PATCH v2 13/16] mm/page_alloc: init local variable buddy

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Date:   Fri, 16 Sep 2022 15:22:54 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>, <david@...hat.com>,
        <osalvador@...e.de>, <anshuman.khandual@....com>
CC:     <willy@...radead.org>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <linmiaohe@...wei.com>
Subject: [PATCH v2 13/16] mm/page_alloc: init local variable buddy_pfn

The local variable buddy_pfn could be passed to buddy_merge_likely()
without initialization if the passed in order is MAX_ORDER - 1. This
looks buggy but buddy_pfn won't be used in this case as there's a
order >= MAX_ORDER - 2 check. Init buddy_pfn to 0 anyway to avoid
possible future misuse.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
Reviewed-by: David Hildenbrand <david@...hat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@....com>
Reviewed-by: Oscar Salvador <osalvador@...e.de>
---
 mm/page_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 67ec8a2e1db2..652b3d766003 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1113,7 +1113,7 @@ static inline void __free_one_page(struct page *page,
 		int migratetype, fpi_t fpi_flags)
 {
 	struct capture_control *capc = task_capc(zone);
-	unsigned long buddy_pfn;
+	unsigned long buddy_pfn = 0;
 	unsigned long combined_pfn;
 	struct page *buddy;
 	bool to_tail;
-- 
2.23.0