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@weissschuh.net Link: https://lore.kernel.org/lkml/9ad51430-b7c0-47dc-80af-20c86539498d@t-8ch.de Reviewed-by: Thomas Weißschuh linux@weissschuh.net Signed-off-by: Zhangjin Wu falcon@tinylab.org --- 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 6b863f7b677c..494195890e4b 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -875,10 +875,10 @@ 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+");