2024-01-23 15:42:29

by Tycho Andersen

[permalink] [raw]
Subject: [PATCH v3 3/3] clone: allow CLONE_THREAD | CLONE_PIDFD together

From: Tycho Andersen <[email protected]>

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 <[email protected]>
---
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 44969cd472f0..25fccf7c08a7 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2296,9 +2296,8 @@ __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 c0624b127fab..a34208c2307e 100644
--- a/tools/testing/selftests/pidfd/pidfd_non_tgl_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_non_tgl_test.c
@@ -546,6 +546,22 @@ static int test_non_tgl_waitid_exec(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)();
@@ -557,6 +573,7 @@ struct pidfd_non_tgl_test {
T(test_non_tgl_exit_poll),
T(test_non_tgl_waitid_exit),
T(test_non_tgl_waitid_exec),
+ T(test_clone_thread_pidfd),
};
#undef T

--
2.34.1