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.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Miaohe Lin <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Reviewed-by: Anshuman Khandual <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3216477d9ba6..4dc2fe575fc8 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;