From: Paul Menage <paul@paulmenage.org>
To: Mike Galbraith <efault@gmx.de>
Cc: LKML <linux-kernel@vger.kernel.org>, Tejun Heo <htejun@gmail.com>,
Li Zefan <lizf@cn.fujitsu.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
David Rientjes <rientjes@google.com>
Subject: Re: patch] cpusets, cgroups: disallow attaching kthreadd
Date: Tue, 18 Oct 2011 21:57:47 -0700 [thread overview]
Message-ID: <CALdu-PDurd4-_jpkhHJ9VuripesWGfUA+Mi8PoyRjJsmxdRqLw@mail.gmail.com> (raw)
In-Reply-To: <1318925436.9641.23.camel@marge.simson.net>
On Tue, Oct 18, 2011 at 1:10 AM, Mike Galbraith <efault@gmx.de> wrote:
>
> Save the user some unexpected trouble, just say no.
>
> Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Paul Menage <paul@paulmenage.org>
>
> ---
> kernel/cpuset.c | 6 ++++--
> kernel/sched.c | 10 ++++++++++
> 2 files changed, 14 insertions(+), 2 deletions(-)
>
> Index: linux-3.0-tip/kernel/cpuset.c
> ===================================================================
> --- linux-3.0-tip.orig/kernel/cpuset.c
> +++ linux-3.0-tip/kernel/cpuset.c
> @@ -59,6 +59,7 @@
> #include <linux/mutex.h>
> #include <linux/workqueue.h>
> #include <linux/cgroup.h>
> +#include <linux/kthread.h>
>
> /*
> * Workqueue for cpuset related tasks.
> @@ -1382,9 +1383,10 @@ static int cpuset_can_attach(struct cgro
> * set of allowed nodes is unnecessary. Thus, cpusets are not
> * applicable for such threads. This prevents checking for success of
> * set_cpus_allowed_ptr() on all attached tasks before cpus_allowed may
> - * be changed.
> + * be changed. We also disallow attaching kthreadd, to prevent it's
> + * child from becoming trapped should it then acquire PF_THREAD_BOUND.
> */
> - if (tsk->flags & PF_THREAD_BOUND)
> + if (tsk->flags & PF_THREAD_BOUND || tsk == kthreadd_task)
> return -EINVAL;
>
> return 0;
> Index: linux-3.0-tip/kernel/sched.c
> ===================================================================
> --- linux-3.0-tip.orig/kernel/sched.c
> +++ linux-3.0-tip/kernel/sched.c
> @@ -71,6 +71,7 @@
> #include <linux/ctype.h>
> #include <linux/ftrace.h>
> #include <linux/slab.h>
> +#include <linux/kthread.h>
>
> #include <asm/tlb.h>
> #include <asm/irq_regs.h>
> @@ -9141,6 +9142,15 @@ cpu_cgroup_destroy(struct cgroup_subsys
> static int
> cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> {
> + /*
> + * kthreadd can fork workers for an RT workqueue in a cgroup
> + * which may or may not have rt_runtime allocated. Just say no,
> + * as attaching a global resource to a non-root group doesn't
> + * make any sense anyway.
> + */
> + if (tsk == kthreadd_task)
> + return -EINVAL;
> +
> #ifdef CONFIG_RT_GROUP_SCHED
> if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
> return -EINVAL;
>
>
>
next prev parent reply other threads:[~2011-10-19 4:58 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-23 6:21 [patch] cpusets: allow PF_THREAD_BOUND kworkers to escape from a cpuset Mike Galbraith
2011-09-23 7:00 ` Li Zefan
2011-09-23 7:19 ` Mike Galbraith
2011-09-23 9:12 ` David Rientjes
2011-09-23 9:42 ` Mike Galbraith
2011-09-23 10:53 ` Mike Galbraith
2011-09-23 13:27 ` David Rientjes
2011-09-23 14:33 ` Mike Galbraith
2011-09-23 18:16 ` Mike Galbraith
2011-09-23 20:20 ` David Rientjes
2011-09-24 3:21 ` Tejun Heo
2011-10-10 5:34 ` Mike Galbraith
2011-10-10 8:03 ` [patch] cpusets, cgroups: disallow attaching kthreadd Mike Galbraith
2011-10-10 16:43 ` Tejun Heo
2011-10-11 2:31 ` Mike Galbraith
2011-10-11 14:08 ` Peter Zijlstra
2011-10-11 16:57 ` Mike Galbraith
2011-10-12 1:22 ` David Rientjes
2011-10-12 1:45 ` Mike Galbraith
2011-10-12 1:20 ` David Rientjes
2011-10-18 8:10 ` patch] " Mike Galbraith
2011-10-18 8:16 ` David Rientjes
2011-10-18 8:42 ` Peter Zijlstra
2011-10-18 8:47 ` Mike Galbraith
2011-10-18 9:06 ` Peter Zijlstra
2011-10-18 9:23 ` Mike Galbraith
2011-10-18 10:11 ` Mike Galbraith
2011-10-18 20:38 ` David Rientjes
2011-10-19 4:00 ` Mike Galbraith
2011-10-19 4:53 ` Paul Menage
2011-10-19 4:56 ` Paul Menage
2011-10-19 5:28 ` Mike Galbraith
2011-10-19 7:50 ` Peter Zijlstra
2011-10-19 19:47 ` David Rientjes
2011-10-20 10:32 ` Peter Zijlstra
2011-10-20 21:24 ` David Rientjes
2011-10-19 4:57 ` Paul Menage [this message]
2011-10-19 5:24 ` [patch-final] " Mike Galbraith
2011-10-19 7:54 ` Peter Zijlstra
2011-10-19 8:00 ` Paul Menage
2011-10-19 8:21 ` Mike Galbraith
2011-10-26 20:27 ` David Rientjes
2011-11-10 20:51 ` David Rientjes
2011-12-06 20:13 ` David Rientjes
2011-12-06 22:47 ` Andrew Morton
2011-12-06 23:53 ` David Rientjes
2011-12-07 0:05 ` Andrew Morton
2011-12-07 3:18 ` [resubmit] " Mike Galbraith
2011-12-07 4:36 ` Mike Galbraith
2011-12-07 22:03 ` David Rientjes
2011-12-14 20:16 ` Andrew Morton
2011-12-15 2:50 ` David Rientjes
2012-01-06 22:06 ` Andrew Morton
2012-01-07 6:34 ` Mike Galbraith
2012-01-07 7:59 ` Andrew Morton
2011-12-07 22:01 ` David Rientjes
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