[RFC 3/3] clone: allow CLONE_THREAD | CLONE_PIDFD together
From: Tycho Andersen <tycho@tycho.pizza>
Date: 2023-11-30 16:41:05
Also in:
lkml
Subsystem:
exec & binfmt api, elf, kernel selftest framework, memory management - core, pidfd api, scheduler, the rest · Maintainers:
Kees Cook, Shuah Khan, Shuah Khan, Andrew Morton, David Hildenbrand, Christian Brauner, Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
From: Tycho Andersen <redacted> This removes the restriction of CLONE_THREAD | CLONE_PIDFD being specified together. Assuming the previous patch sorts out all the thorny issues this should be safe. I've left it as a separate patch since it is not strictly necessary as a usecase for us, but might be nice? Perhaps we want to wait until someone actually needs it though. Signed-off-by: Tycho Andersen <redacted> --- kernel/fork.c | 3 +-- .../selftests/pidfd/pidfd_non_tgl_test.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index eef15c93f6cf..ada476f38b56 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c@@ -2302,9 +2302,8 @@ __latent_entropy struct task_struct *copy_process( /* * - CLONE_DETACHED is blocked so that we can potentially * reuse it later for CLONE_PIDFD. - * - CLONE_THREAD is blocked until someone really needs it. */ - if (clone_flags & (CLONE_DETACHED | CLONE_THREAD)) + if (clone_flags & CLONE_DETACHED) return ERR_PTR(-EINVAL); }
diff --git a/tools/testing/selftests/pidfd/pidfd_non_tgl_test.c b/tools/testing/selftests/pidfd/pidfd_non_tgl_test.c
index e3992f2d88cf..dfd6a2cd85a3 100644
--- a/tools/testing/selftests/pidfd/pidfd_non_tgl_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_non_tgl_test.c@@ -305,6 +305,22 @@ static int test_non_tgl_exit(void) return ret; } +static int test_clone_thread_pidfd(void) +{ + pid_t pid; + int flags = CLONE_THREAD | CLONE_VM | CLONE_SIGHAND | CLONE_PIDFD; + int pidfd; + + pid = clone(thread_sleep, stack + STACK_SIZE, flags, NULL, &pidfd); + if (pid < 0) { + perror("clone"); + return KSFT_FAIL; + } + + close(pidfd); + return KSFT_PASS; +} + #define T(x) { x, #x } struct pidfd_non_tgl_test { int (*fn)();
@@ -313,6 +329,7 @@ struct pidfd_non_tgl_test { T(test_non_tgl_basic), T(test_non_tgl_exec), T(test_non_tgl_exit), + T(test_clone_thread_pidfd), }; #undef T
--
2.34.1