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Biederman" , Tycho Andersen , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] pidfd: clone: allow CLONE_THREAD | CLONE_PIDFD together Message-ID: <20240205145532.GA28823@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790071310918795807 X-GMAIL-MSGID: 1790071310918795807 copy_process() just needs to pass PIDFD_THREAD to __pidfd_prepare() if clone_flags & CLONE_THREAD. We can also add another CLONE_ flag (or perhaps reuse CLONE_DETACHED) to enforce PIDFD_THREAD without CLONE_THREAD. Originally-from: Tycho Andersen Signed-off-by: Oleg Nesterov Reviewed-by: Tycho Andersen --- kernel/fork.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index 8d08a2d1b095..cd61ca87d0e6 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2311,9 +2311,8 @@ __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); } @@ -2536,8 +2535,10 @@ __latent_entropy struct task_struct *copy_process( * if the fd table isn't shared). */ if (clone_flags & CLONE_PIDFD) { + int flags = (clone_flags & CLONE_THREAD) ? PIDFD_THREAD : 0; + /* Note that no task has been attached to @pid yet. */ - retval = __pidfd_prepare(pid, 0, &pidfile); + retval = __pidfd_prepare(pid, flags, &pidfile); if (retval < 0) goto bad_fork_free_pid; pidfd = retval;