From 44a887d021de8f76183132bb5892c2c0840d3aca Mon Sep 17 00:00:00 2001 From: Paul Durrant Date: Tue, 16 Jul 2019 13:29:02 +0200 Subject: [PATCH] mm.h: fix BUG_ON() condition in put_page_alloc_ref() The BUG_ON() was misplaced when this function was introduced in commit ec83f825 "mm.h: add helper function to test-and-clear _PGC_allocated". It will fire incorrectly if _PGC_allocated is already clear on entry. Thus it should be moved after the if statement. Signed-off-by: Paul Durrant Reviewed-by: Jan Beulich --- xen/include/xen/mm.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h index 5d0c19f011..cfea38f801 100644 --- a/xen/include/xen/mm.h +++ b/xen/include/xen/mm.h @@ -667,9 +667,11 @@ static inline void put_page_alloc_ref(struct page_info *page) * the caller holding an additional reference. I.e. the allocation * reference must never be the last reference held. */ - BUG_ON((page->count_info & PGC_count_mask) <= 1); if ( test_and_clear_bit(_PGC_allocated, &page->count_info) ) + { + BUG_ON((page->count_info & PGC_count_mask) <= 1); put_page(page); + } } #endif /* __XEN_MM_H__ */ -- 2.30.2