The vfprintf test case require to open a temporary file to write, the
old memfd_create() method is perfect but has strong dependency on
MEMFD_CREATE and also TMPFS or HUGETLBFS (see fs/Kconfig):
config MEMFD_CREATE
def_bool TMPFS || HUGETLBFS
And from v6.2, MFD_NOEXEC_SEAL must be passed for the non-executable
memfd, otherwise, The kernel warning will be output to the test result
like this:
Running test 'vfprintf'
0 emptymemfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=1 'init'
"" = "" [OK]
To avoid such warning and also to remove the MEMFD_CREATE dependency,
let's open a file from tmpfs directly.
The /tmp directory is used to detect the existing of tmpfs, if not
there, skip instead of fail.
And further, for pid == 1, the initramfs is loaded as ramfs, which can
be used as tmpfs, so, it is able to further remove TMPFS dependency too.
Suggested-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/9ad51430-b7c0-47dc-80af-20c86539498d@xxxxxxxx
Signed-off-by: Zhangjin Wu <falcon@xxxxxxxxxxx>
---
tools/testing/selftests/nolibc/nolibc-test.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 0ca7d011765a..0847813d756c 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -888,10 +888,10 @@ static int expect_vfprintf(int llen, size_t c, const char *expected, const char
FILE *memfile;
va_list args;
- fd = memfd_create("vfprintf", 0);
+ fd = open("/tmp", O_TMPFILE | O_EXCL | O_RDWR, 0600);
if (fd == -1) {
- pad_spc(llen, 64, "[FAIL]\n");
- return 1;
+ pad_spc(llen, 64, "[SKIPPED]\n");
+ return 0;
}
memfile = fdopen(fd, "w+");
--
2.25.1
