From 1605ce99afac80cd6080c821a664921c19eb3e00 Mon Sep 17 00:00:00 2001 From: Hongfu Li Date: Fri, 17 Jul 2026 15:02:51 +0800 Subject: [PATCH] selftests/mm: fix BUG_ON checking wrong variable in mremap_dontunmap In mremap_dontunmap_partial_mapping_overwrite(), mremap() stores its returned remapped address into remapped_mapping, while the BUG_ON incorrectly checks dest_mapping instead. If mremap() fails, dest_mapping still holds a valid pointer obtained from the prior mmap() call, making this BUG_ON never trigger at all. Correct the check to validate the actual mremap() return value stored in remapped_mapping. Link: https://lore.kernel.org/20260717070251.73212-1-hongfu.li@linux.dev Signed-off-by: Hongfu Li Reviewed-by: SJ Park Cc: David Hildenbrand Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/mremap_dontunmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/mremap_dontunmap.c b/tools/testing/selftests/mm/mremap_dontunmap.c index a4f75d836733..96ba537facf7 100644 --- a/tools/testing/selftests/mm/mremap_dontunmap.c +++ b/tools/testing/selftests/mm/mremap_dontunmap.c @@ -313,7 +313,7 @@ static void mremap_dontunmap_partial_mapping_overwrite(void) mremap(source_mapping, 5 * page_size, 5 * page_size, MREMAP_DONTUNMAP | MREMAP_MAYMOVE | MREMAP_FIXED, dest_mapping); - BUG_ON(dest_mapping == MAP_FAILED, "mremap"); + BUG_ON(remapped_mapping == MAP_FAILED, "mremap"); BUG_ON(dest_mapping != remapped_mapping, "expected to remap to dest_mapping"); BUG_ON(check_region_contains_byte(source_mapping, 5 * page_size, 0) !=