Messages in this thread | | | Date | Fri, 20 Dec 2019 21:36:50 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 2/3] clone3: allow spawning processes into cgroups |
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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.
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