The patch titled Subject: selftests/memfd: run sysctl tests when PID namespace support is enabled has been added to the -mm mm-hotfixes-unstable branch. Its filename is selftests-memfd-run-sysctl-tests-when-pid-namespace-support-is-enabled.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-memfd-run-sysctl-tests-when-pid-namespace-support-is-enabled.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Isaac J. Manjarres" <isaacmanjarres@xxxxxxxxxx> Subject: selftests/memfd: run sysctl tests when PID namespace support is enabled Date: Thu, 5 Dec 2024 11:29:41 -0800 The sysctl tests for vm.memfd_noexec rely on the kernel to support PID namespaces (i.e. the kernel is built with CONFIG_PID_NS=y). If the kernel the test runs on does not support PID namespaces, the first sysctl test will fail when attempting to spawn a new thread in a new PID namespace, abort the test, preventing the remaining tests from being run. This is not desirable, as not all kernels need PID namespaces, but can still use the other features provided by memfd. Therefore, only run the sysctl tests if the kernel supports PID namespaces. Otherwise, skip those tests and emit an informative message to let the user know why the sysctl tests are not being run. Link: https://lkml.kernel.org/r/20241205192943.3228757-1-isaacmanjarres@xxxxxxxxxx Fixes: 11f75a01448f ("selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC") Signed-off-by: Isaac J. Manjarres <isaacmanjarres@xxxxxxxxxx> Reviewed-by: Jeff Xu <jeffxu@xxxxxxxxxx> Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx> Cc: Kalesh Singh <kaleshsingh@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> [6.6+] Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/memfd/memfd_test.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/tools/testing/selftests/memfd/memfd_test.c~selftests-memfd-run-sysctl-tests-when-pid-namespace-support-is-enabled +++ a/tools/testing/selftests/memfd/memfd_test.c @@ -9,6 +9,7 @@ #include <fcntl.h> #include <linux/memfd.h> #include <sched.h> +#include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <signal.h> @@ -1599,6 +1600,11 @@ static void test_share_fork(char *banner close(fd); } +static bool pid_ns_supported(void) +{ + return access("/proc/self/ns/pid", F_OK) == 0; +} + int main(int argc, char **argv) { pid_t pid; @@ -1634,8 +1640,12 @@ int main(int argc, char **argv) test_seal_grow(); test_seal_resize(); - test_sysctl_simple(); - test_sysctl_nested(); + if (pid_ns_supported()) { + test_sysctl_simple(); + test_sysctl_nested(); + } else { + printf("PID namespaces are not supported; skipping sysctl tests\n"); + } test_share_dup("SHARE-DUP", ""); test_share_mmap("SHARE-MMAP", ""); _ Patches currently in -mm which might be from isaacmanjarres@xxxxxxxxxx are selftests-memfd-run-sysctl-tests-when-pid-namespace-support-is-enabled.patch