Re: [PATCH v7 0/7] selftests/mm: skip several tests when thp is not available

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

On Mon, 30 Mar 2026 23:14:56 +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.

> Changes in v7:
>   - patch 1 add reviewed-by from Lorenzo
>   - patch 4 new patch to make ksft_exit_fail_perror variable length
>     arguments
>   - patch 5 change to use %.*s to print the buf when error happened
>     Limit the buflen arg as 2 minimum. Check the error path (numwritten
> 	< 0).
>     And use the ksft_exit_fail_perror to print the logs in error path

Here's how v7 altered mm.git.


 tools/testing/selftests/kselftest.h  |   21 ++++++++++++++++++---
 tools/testing/selftests/mm/vm_util.c |   14 +++++++-------
 2 files changed, 25 insertions(+), 10 deletions(-)

--- a/tools/testing/selftests/kselftest.h~b
+++ a/tools/testing/selftests/kselftest.h
@@ -43,7 +43,7 @@
  * the program is aborting before finishing all tests):
  *
  *    ksft_exit_fail_msg(fmt, ...);
- *    ksft_exit_fail_perror(msg);
+ *    ksft_exit_fail_perror(fmt, ...);
  *
  */
 #ifndef __KSELFTEST_H
@@ -417,9 +417,24 @@ static inline __noreturn __printf(1, 2)
 	exit(KSFT_FAIL);
 }
 
-static inline __noreturn void ksft_exit_fail_perror(const char *msg)
+static inline __noreturn __printf(1, 2) void ksft_exit_fail_perror(const char *msg, ...)
 {
-	ksft_exit_fail_msg("%s: %s (%d)\n", msg, strerror(errno), errno);
+	va_list args;
+	char *buf = NULL;
+	int saved_errno = errno;
+
+	va_start(args, msg);
+	if (vasprintf(&buf, msg, args) == -1) {
+		va_end(args);
+		ksft_exit_fail_msg("vasprintf failed: %s (%d)\n", strerror(saved_errno),
+				saved_errno);
+	}
+	va_end(args);
+
+	errno = saved_errno;
+	ksft_exit_fail_msg("%s: %s (%d)\n", buf, strerror(errno), errno);
+
+	free(buf);
 }
 
 static inline __noreturn void ksft_exit_xfail(void)
--- a/tools/testing/selftests/mm/vm_util.c~b
+++ a/tools/testing/selftests/mm/vm_util.c
@@ -782,21 +782,21 @@ void write_file(const char *path, const
 	int fd, saved_errno;
 	ssize_t numwritten;
 
-	if (buflen < 1)
+	if (buflen < 2)
 		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));
+		ksft_exit_fail_perror("%s open failed", path);
 
 	numwritten = write(fd, buf, buflen - 1);
 	saved_errno = errno;
 	close(fd);
 	errno = saved_errno;
-	if (numwritten < 1)
-		ksft_exit_fail_msg("%s write(%s) failed: %s\n", path, buf,
-				strerror(errno));
+	if (numwritten < 0)
+		ksft_exit_fail_perror("%s write(%.*s) failed", path, (int)(buflen - 1),
+				buf);
 	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);
+		ksft_exit_fail_msg("%s write(%.*s) is truncated, expected %zu bytes, got %zd bytes\n",
+				path, (int)(buflen - 1), buf, buflen - 1, numwritten);
 }
_