From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <christian.brauner@ubuntu.com>
Cc: linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
Tejun Heo <tj@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Li Zefan <lizefan@huawei.com>,
Peter Zijlstra <peterz@infradead.org>,
cgroups@vger.kernel.org
Subject: Re: [PATCH 2/3] clone3: allow spawning processes into cgroups
Date: Fri, 20 Dec 2019 21:36:50 +0100 [thread overview]
Message-ID: <20191220203650.GA15133@redhat.com> (raw)
In-Reply-To: <20191218173516.7875-3-christian.brauner@ubuntu.com>
On 12/18, Christian Brauner wrote:
>
> This adds support for creating a process in a different cgroup than its
> parent.
Cough... I will not comment the intent ;) I can't review the cgroup patches
anyway.
However,
> +int cgroup_lock_fork(struct kernel_clone_args *kargs)
> + __acquires(&cgroup_mutex)
> +{
> + struct cgroup *cgrp;
> +
> + if (!(kargs->flags & CLONE_INTO_CGROUP))
> + return 0;
> +
> + cgrp = kargs->cgrp;
> + if (!cgrp)
> + return 0;
> +
> + mutex_lock(&cgroup_mutex);
> +
> + if (!cgroup_is_dead(cgrp))
> + return 0;
> +
> + mutex_unlock(&cgroup_mutex);
> + return -ENODEV;
...
> @@ -2172,7 +2172,7 @@ static __latent_entropy struct task_struct *copy_process(
> * between here and cgroup_post_fork() if an organisation operation is in
> * progress.
> */
> - retval = cgroup_can_fork(p);
> + retval = cgroup_can_fork(current, p, args);
> if (retval)
> goto bad_fork_cgroup_threadgroup_change_end;
>
> @@ -2226,6 +2226,10 @@ static __latent_entropy struct task_struct *copy_process(
> goto bad_fork_cancel_cgroup;
> }
>
> + retval = cgroup_lock_fork(args);
mutex_lock() under spin_lock() ??
just in case, note that mutex_lock(&cgroup_mutex) is not safe even under
cgroup_threadgroup_change_begin(), this can deadlock.
Oleg.
next prev parent reply other threads:[~2019-12-20 20:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 17:35 [PATCH 0/3] clone3 & cgroups: allow spawning processes into cgroups Christian Brauner
2019-12-18 17:35 ` [PATCH 1/3] cgroup: unify attach permission checking Christian Brauner
2019-12-18 23:46 ` Christian Brauner
2019-12-19 0:39 ` Christian Brauner
2019-12-18 17:35 ` [PATCH 2/3] clone3: allow spawning processes into cgroups Christian Brauner
2019-12-20 20:36 ` Oleg Nesterov [this message]
2019-12-18 17:35 ` [PATCH 3/3] selftests/cgroup: add tests for cloning " Christian Brauner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191220203650.GA15133@redhat.com \
--to=oleg@redhat.com \
--cc=cgroups@vger.kernel.org \
--cc=christian.brauner@ubuntu.com \
--cc=hannes@cmpxchg.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lizefan@huawei.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).