From 053cfda102306a3394012f9fe2594811c34925e4 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Wed, 8 Sep 2021 18:10:11 -0700 Subject: [PATCH] mm/page_alloc.c: avoid accessing uninitialized pcp page migratetype If it's not prepared to free unref page, the pcp page migratetype is unset. Thus we will get rubbish from get_pcppage_migratetype() and might list_del(&page->lru) again after it's already deleted from the list leading to grumble about data corruption. Link: https://lkml.kernel.org/r/20210902115447.57050-1-linmiaohe@huawei.com Fixes: df1acc856923 ("mm/page_alloc: avoid conflating IRQs disabled with zone->lock") Signed-off-by: Miaohe Lin Acked-by: Mel Gorman Acked-by: Vlastimil Babka Reviewed-by: David Hildenbrand Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index de309a1..b37435c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3428,8 +3428,10 @@ void free_unref_page_list(struct list_head *list) /* Prepare pages for freeing */ list_for_each_entry_safe(page, next, list, lru) { pfn = page_to_pfn(page); - if (!free_unref_page_prepare(page, pfn, 0)) + if (!free_unref_page_prepare(page, pfn, 0)) { list_del(&page->lru); + continue; + } /* * Free isolated pages directly to the allocator, see -- 2.7.4