From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <christian@brauner.io>
Cc: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
jannh@google.com, dhowells@redhat.com, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org, serge@hallyn.com, luto@kernel.org,
arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org,
tglx@linutronix.de, mtk.manpages@gmail.com,
akpm@linux-foundation.org, cyphar@cyphar.com,
joel@joelfernandes.org, dancol@google.com
Subject: Re: [PATCH v2 2/5] clone: add CLONE_PIDFD
Date: Thu, 18 Apr 2019 15:12:07 +0200 [thread overview]
Message-ID: <20190418131206.GB13701@redhat.com> (raw)
In-Reply-To: <20190418101841.4476-3-christian@brauner.io>
On 04/18, Christian Brauner wrote:
>
> @@ -1674,13 +1729,14 @@ static __latent_entropy struct task_struct *copy_process(
> unsigned long clone_flags,
> unsigned long stack_start,
> unsigned long stack_size,
> + int __user *parent_tidptr,
> int __user *child_tidptr,
> struct pid *pid,
> int trace,
> unsigned long tls,
> int node)
> {
> - int retval;
> + int pidfd = -1, retval;
it seems that initialization is unneeded, but this is cosmetic.
I see no technical problems, feel free to add my reviewed-by.
But let me ask a couple of questions...
Why O_CLOEXEC? I am just curious, I do not really care.
Should we allow CLONE_THREAD | CLONE_PIDFD ?
Are you sure we will never need to extend this interface? If not, then perhaps it
make sense to add something like
if (CLONE_PIDFD) {
unsigned long not_used_yet;
if (get_user(not_used_yet, parent_tidptr) ||
not_used_yet != 0)
return -EINVAL;
}
this way we can easily add more arguments in future or even turn CLONE_PIDFD into
CLONE_MORE_ARGS_IN_PARENT_TIDPTR.
Not that I think this is really good idea, sys_clone2() makes more sense, but still.
Oleg.
next prev parent reply other threads:[~2019-04-18 13:12 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-18 10:18 [PATCH v2 0/5] clone: add CLONE_PIDFD Christian Brauner
2019-04-18 10:18 ` [PATCH v2 1/5] Make anon_inodes unconditional Christian Brauner
2019-04-18 10:18 ` [PATCH v2 2/5] clone: add CLONE_PIDFD Christian Brauner
2019-04-18 13:12 ` Oleg Nesterov [this message]
2019-04-18 13:28 ` Christian Brauner
2019-04-18 14:10 ` Oleg Nesterov
2019-04-18 14:15 ` Christian Brauner
2019-04-19 13:39 ` Aleksa Sarai
2019-04-18 10:18 ` [PATCH v2 3/5] signal: use fdget() since we don't allow O_PATH Christian Brauner
2019-04-18 13:17 ` Oleg Nesterov
2019-04-18 15:37 ` Linus Torvalds
2019-04-18 15:53 ` Christian Brauner
2019-04-18 10:18 ` [PATCH v2 4/5] signal: support CLONE_PIDFD with pidfd_send_signal Christian Brauner
2019-04-18 14:26 ` Oleg Nesterov
2019-04-18 15:01 ` Christian Brauner
2019-04-18 10:18 ` [PATCH v2 5/5] samples: show race-free pidfd metadata access Christian Brauner
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