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

[Andrew Morton]

On Mon, 30 Mar 2026 23:14:56 +0800 Chunyu Hu <ch...@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);
 }
_