mmap() in test_ra_error() is not checked for MAP_FAILED. On failure,
the subsequent write *paste_addr = 1 dereferences an invalid pointer
and segfaults. Add a FAIL_IF() check, consistent with the rest of the
function.

Fixes: 0f4ef8a3bf78 ("selftests/powerpc: Add test for real address error handling")
Signed-off-by: longlong yan <redacted>
---
 tools/testing/selftests/powerpc/mce/inject-ra-err.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/powerpc/mce/inject-ra-err.c b/tools/testing/selftests/powerpc/mce/inject-ra-err.c
index 94323c34d9a6..0622fd814114 100644
--- a/tools/testing/selftests/powerpc/mce/inject-ra-err.c
+++ b/tools/testing/selftests/powerpc/mce/inject-ra-err.c

@@ -47,6 +47,7 @@ static int test_ra_error(void)
 	FAIL_IF(sigaction(SIGBUS, &act, NULL) != 0);
 
 	paste_addr = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0ULL);
+	FAIL_IF(paste_addr == MAP_FAILED);
 
 	/* The following assignment triggers exception */
 	mb();

-- 
2.43.0