Re: [PATCH v6 0/6] selftests/mm: skip several tests when thp is not available

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 24 Mar 2026 09:33:10 +0800 Chunyu Hu <chuhu@redhat.com> wrote:

> There are several tests requires transprarent hugepages, when run on thp
> disabled kernel such as realtime kernel, there will be false negative.
> Mark those tests as skip when thp is not available.

Thanks, I updated mm.git's mm-unstable branch to this version.

> Chagnes in v6:
>   - patch 3 add reviewed-by from Lorenzo
>   - patch 4 handle the errno before and after close(), suggested by AI

Here's how v6 altered mm.git:


 tools/testing/selftests/mm/vm_util.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/tools/testing/selftests/mm/vm_util.c~b
+++ a/tools/testing/selftests/mm/vm_util.c
@@ -785,15 +785,23 @@ int unpoison_memory(unsigned long pfn)
 
 void write_file(const char *path, const char *buf, size_t buflen)
 {
-	int fd;
+	int fd, saved_errno;
 	ssize_t numwritten;
+	if (buflen < 1)
+		ksft_exit_fail_msg("Incorrect buffer len: %zu\n", buflen);
 
 	fd = open(path, O_WRONLY);
 	if (fd == -1)
 		ksft_exit_fail_msg("%s open failed: %s\n", path, strerror(errno));
 
 	numwritten = write(fd, buf, buflen - 1);
+	saved_errno = errno;
 	close(fd);
+	errno = saved_errno;
 	if (numwritten < 1)
-		ksft_exit_fail_msg("Write failed\n");
+		ksft_exit_fail_msg("%s write(%s) failed: %s\n", path, buf,
+				strerror(errno));
+	if (numwritten != buflen - 1)
+		ksft_exit_fail_msg("%s write(%s) is truncated, expected %zu bytes, got %zd bytes\n",
+				path, buf, buflen - 1, numwritten);
 }
_