On Fri, Apr 14, 2023 at 02:28:01AM +0000, jeffxu@chromium.org wrote:

From: Jeff Xu jeffxu@google.com

sysctl memfd_noexec is pid-namespaced, non-reservable, and inherent to the child process. Moving the inherence test from init ns to child ns, so init ns can keep the default value.

Signed-off-by: Jeff Xu jeffxu@google.com Reported-by: kernel test robot yujie.liu@intel.com Link: https://lore.kernel.org/oe-lkp/202303312259.441e35db-yujie.liu@intel.com

The reported issue is gone after applying this patch. Thanks.

Tested-by: Yujie Liu yujie.liu@intel.com

========================================================================================= compiler/group/kconfig/rootfs/tbox_group/testcase: gcc-11/group-02/x86_64-rhel-8.3-kselftests/debian-12-x86_64-20220629.cgz/lkp-skl-d06/kernel-selftests

commit: c4f75bc8bd6b3 ("mm/memfd: add write seals when apply SEAL_EXEC to executable memfd") 11f75a01448f1 ("selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC") 395874d592d77 ("selftests/memfd: fix test_sysctl")

c4f75bc8bd6b3d62 11f75a01448f1b7a739e75dbd8f 395874d592d775d999d18ef9cae ---------------- --------------------------- --------------------------- fail:runs %reproduction fail:runs %reproduction fail:runs | | | | | :6 233% 14:20 0% :5 kernel-selftests.memfd.run_fuse_test.sh.fail

---

tools/testing/selftests/memfd/memfd_test.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index ae71f15f790d..dba0e8ba002f 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -43,6 +43,9 @@ */ static size_t mfd_def_size = MFD_DEF_SIZE; static const char *memfd_str = MEMFD_STR; +static pid_t spawn_newpid_thread(unsigned int flags, int (*fn)(void *)); +static int newpid_thread_fn2(void *arg); +static void join_newpid_thread(pid_t pid); static ssize_t fd2name(int fd, char *buf, size_t bufsize) { @@ -1111,6 +1114,7 @@ static void test_noexec_seal(void) static void test_sysctl_child(void) { int fd;

• int pid;

printf("%s sysctl 0\n", memfd_str); sysctl_assert_write("0"); @@ -1129,6 +1133,10 @@ static void test_sysctl_child(void) mfd_def_size, MFD_CLOEXEC | MFD_ALLOW_SEALING);

• printf("%s child ns\n", memfd_str);
• pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn2);
• join_newpid_thread(pid);
• mfd_assert_mode(fd, 0666); mfd_assert_has_seals(fd, F_SEAL_EXEC); mfd_fail_chmod(fd, 0777);

@@ -1206,12 +1214,6 @@ static void test_sysctl(void) int pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn); join_newpid_thread(pid);

• printf("%s child ns\n", memfd_str);
• sysctl_assert_write("1");
• pid = spawn_newpid_thread(CLONE_NEWPID, newpid_thread_fn2);
• join_newpid_thread(pid);

} /* -- 2.40.0.577.gac1e443424-goog