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Message-ID: <20240205145532.GA28823@redhat.com>
Date: Mon, 5 Feb 2024 15:55:32 +0100
From: Oleg Nesterov <oleg@...hat.com>
To: Christian Brauner <brauner@...nel.org>
Cc: Andy Lutomirski <luto@...capital.net>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Tycho Andersen <tycho@...ho.pizza>, linux-api@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] pidfd: clone: allow CLONE_THREAD | CLONE_PIDFD together
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 <tycho@...ho.pizza>
Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
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;
--
2.25.1.362.g51ebf55
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