[PATCH] selftests/mm: Fix mmap() return value check in run_migration_benchmark

[Hongfu Li]

mmap() returns MAP_FAILED on error, not NULL.  The current check uses
!buffer->ptr, which evaluates to false when mmap() fails (since
MAP_FAILED is (void *)-1, not 0), so the error path is never taken.

Signed-off-by: Hongfu Li <lihongfu@xxxxxxxxxx>
---
 tools/testing/selftests/mm/hmm-tests.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftests/mm/hmm-tests.c
index 788689497e92..d72adba5c74e 100644
--- a/tools/testing/selftests/mm/hmm-tests.c
+++ b/tools/testing/selftests/mm/hmm-tests.c
@@ -2688,7 +2688,7 @@ static inline int run_migration_benchmark(int fd, int use_thp, size_t buffer_siz
 	buffer->ptr = mmap(NULL, buffer_size, PROT_READ | PROT_WRITE,
 			  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 
-	if (!buffer->ptr)
+	if (buffer->ptr == MAP_FAILED)
 		return -1;
 
 	/* Apply THP hint if requested */
-- 
2.25.1