From: Joel Fernandes <joel@joelfernandes.org>
To: Chris Hyser <chris.hyser@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Josh Don <joshdon@google.com>, Ingo Molnar <mingo@kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Mel Gorman <mgorman@suse.de>, LKML <linux-kernel@vger.kernel.org>,
Thomas Glexiner <tglx@linutronix.de>
Subject: Re: [PATCH 17/19] sched: Inherit task cookie on fork()
Date: Mon, 10 May 2021 16:47:24 -0400 [thread overview]
Message-ID: <CAEXW_YSX79vR9hdkjKcf08uZk85xhC8nOnesf8s6Cvp2kqKoFA@mail.gmail.com> (raw)
In-Reply-To: <3dbce4ff-44ed-73ca-2ea1-97b126dd664e@oracle.com>
On Mon, May 10, 2021 at 12:23 PM Chris Hyser <chris.hyser@oracle.com> wrote:
>
> On 5/10/21 12:06 PM, Joel Fernandes wrote:
> > Hi Peter,
> >
> > On Thu, Apr 22, 2021 at 8:36 AM Peter Zijlstra <peterz@infradead.org> wrote:
> >>
> >> Note that sched_core_fork() is called from under tasklist_lock, and
> >> not from sched_fork() earlier. This avoids a few races later.
> >>
> >> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> >> ---
> >> include/linux/sched.h | 2 ++
> >> kernel/fork.c | 3 +++
> >> kernel/sched/core_sched.c | 6 ++++++
> >> 3 files changed, 11 insertions(+)
> >>
> >> --- a/include/linux/sched.h
> >> +++ b/include/linux/sched.h
> >> @@ -2172,8 +2172,10 @@ const struct cpumask *sched_trace_rd_spa
> >>
> >> #ifdef CONFIG_SCHED_CORE
> >> extern void sched_core_free(struct task_struct *tsk);
> >> +extern void sched_core_fork(struct task_struct *p);
> >> #else
> >> static inline void sched_core_free(struct task_struct *tsk) { }
> >> +static inline void sched_core_fork(struct task_struct *p) { }
> >> #endif
> >>
> >> #endif
> >> --- a/kernel/fork.c
> >> +++ b/kernel/fork.c
> >> @@ -2249,6 +2249,8 @@ static __latent_entropy struct task_stru
> >>
> >> klp_copy_process(p);
> >>
> >> + sched_core_fork(p);
> >> +
> >> spin_lock(¤t->sighand->siglock);
> >>
> >> /*
> >> @@ -2336,6 +2338,7 @@ static __latent_entropy struct task_stru
> >> return p;
> >>
> >> bad_fork_cancel_cgroup:
> >> + sched_core_free(p);
> >> spin_unlock(¤t->sighand->siglock);
> >> write_unlock_irq(&tasklist_lock);
> >> cgroup_cancel_fork(p, args);
> >> --- a/kernel/sched/core_sched.c
> >> +++ b/kernel/sched/core_sched.c
> >> @@ -100,6 +100,12 @@ static unsigned long sched_core_clone_co
> >> return cookie;
> >> }
> >>
> >> +void sched_core_fork(struct task_struct *p)
> >> +{
> >> + RB_CLEAR_NODE(&p->core_node);
> >> + p->core_cookie = sched_core_clone_cookie(current);
> >
> > Does this make sense also for !CLONE_THREAD forks?
>
> Yes. Given the absence of a cgroup interface, fork inheritance (clone the cookie) is the best way to create shared
> cookie hierarchies. The security issue you mentioned was handled in my original code by setting a unique cookie on
> 'exec', but Peter took that out for the reason mentioned above. It was part of the "lets get this in compromise" effort.
Thanks for sharing the history of it. I guess one can argue that this
policy is better to be hardcoded in userspace since core-scheduling
can be used for non-security usecases as well. Maybe one could simply
call the prctl(2) from userspace if they so desire, before calling
exec() ?
- Joel
next prev parent reply other threads:[~2021-05-10 20:47 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 12:04 [PATCH 00/19] sched: Core Scheduling Peter Zijlstra
2021-04-22 12:05 ` [PATCH 01/19] sched/fair: Add a few assertions Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-05-13 8:56 ` Ning, Hongyu
2021-04-22 12:05 ` [PATCH 02/19] sched: Provide raw_spin_rq_*lock*() helpers Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 03/19] sched: Wrap rq::lock access Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 04/19] sched: Prepare for Core-wide rq->lock Peter Zijlstra
2021-04-24 1:22 ` Josh Don
2021-04-26 8:31 ` Peter Zijlstra
2021-04-26 22:21 ` Josh Don
2021-04-27 17:10 ` Don Hiatt
2021-04-27 23:35 ` Josh Don
2021-04-28 1:03 ` Aubrey Li
2021-04-28 6:05 ` Aubrey Li
2021-04-28 10:57 ` Aubrey Li
2021-04-28 16:41 ` Don Hiatt
2021-04-29 20:48 ` Josh Don
2021-04-29 21:09 ` Don Hiatt
2021-04-29 23:22 ` Josh Don
2021-04-30 16:18 ` Don Hiatt
2021-04-30 8:26 ` Aubrey Li
2021-04-28 16:04 ` Don Hiatt
2021-04-27 23:30 ` Josh Don
2021-04-28 9:13 ` Peter Zijlstra
2021-04-28 10:35 ` Aubrey Li
2021-04-28 11:03 ` Peter Zijlstra
2021-04-28 14:18 ` Paul E. McKenney
2021-04-29 20:11 ` Josh Don
2021-05-03 19:17 ` Peter Zijlstra
2021-04-28 7:13 ` Peter Zijlstra
2021-04-28 6:02 ` Aubrey Li
2021-04-29 8:03 ` Aubrey Li
2021-04-29 20:39 ` Josh Don
2021-04-30 8:20 ` Aubrey Li
2021-04-30 8:48 ` Josh Don
2021-04-30 14:15 ` Aubrey Li
2021-05-04 7:38 ` Peter Zijlstra
2021-05-05 16:20 ` Don Hiatt
2021-05-06 10:25 ` Peter Zijlstra
2021-05-07 9:50 ` [PATCH v2 " Peter Zijlstra
2021-05-08 8:07 ` Aubrey Li
2021-05-12 9:07 ` Peter Zijlstra
2021-04-22 12:05 ` [PATCH 05/19] sched: " Peter Zijlstra
2021-05-07 9:50 ` [PATCH v2 " Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 06/19] sched: Optimize rq_lockp() usage Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 07/19] sched: Allow sched_core_put() from atomic context Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 08/19] sched: Introduce sched_class::pick_task() Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 09/19] sched: Basic tracking of matching tasks Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 10/19] sched: Add core wide task selection and scheduling Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 11/19] sched/fair: Fix forced idle sibling starvation corner case Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Vineeth Pillai
2021-04-22 12:05 ` [PATCH 12/19] sched: Fix priority inversion of cookied task with sibling Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Joel Fernandes (Google)
2021-04-22 12:05 ` [PATCH 13/19] sched/fair: Snapshot the min_vruntime of CPUs on force idle Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Joel Fernandes (Google)
2021-04-22 12:05 ` [PATCH 14/19] sched: Trivial forced-newidle balancer Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 15/19] sched: Migration changes for core scheduling Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Aubrey Li
2021-04-22 12:05 ` [PATCH 16/19] sched: Trivial core scheduling cookie management Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 17/19] sched: Inherit task cookie on fork() Peter Zijlstra
2021-05-10 16:06 ` Joel Fernandes
2021-05-10 16:22 ` Chris Hyser
2021-05-10 20:47 ` Joel Fernandes [this message]
2021-05-10 21:38 ` Chris Hyser
2021-05-12 9:05 ` Peter Zijlstra
2021-05-12 20:20 ` Josh Don
2021-05-12 21:07 ` Don Hiatt
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 18/19] sched: prctl() core-scheduling interface Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Chris Hyser
2021-06-14 23:36 ` [PATCH 18/19] " Josh Don
2021-06-15 11:31 ` Joel Fernandes
2021-08-05 16:53 ` Eugene Syromiatnikov
2021-08-05 17:00 ` Peter Zijlstra
2021-08-17 15:15 ` Eugene Syromiatnikov
2021-08-17 15:52 ` Peter Zijlstra
2021-08-17 23:17 ` Eugene Syromiatnikov
2021-08-19 11:09 ` [PATCH] sched: Fix Core-wide rq->lock for uninitialized CPUs Peter Zijlstra
2021-08-19 15:50 ` Tao Zhou
2021-08-19 16:19 ` Eugene Syromiatnikov
2021-08-20 0:18 ` Josh Don
2021-08-20 10:02 ` Peter Zijlstra
2021-08-23 9:07 ` [tip: sched/urgent] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 19/19] kselftest: Add test for core sched prctl interface Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Chris Hyser
2021-04-22 16:43 ` [PATCH 00/19] sched: Core Scheduling Don Hiatt
2021-04-22 17:29 ` Peter Zijlstra
2021-04-30 6:47 ` Ning, Hongyu
2021-05-06 10:29 ` Peter Zijlstra
2021-05-06 12:53 ` Ning, Hongyu
2021-05-07 18:02 ` Joel Fernandes
2021-05-10 16:16 ` Vincent Guittot
2021-05-11 7:00 ` Vincent Guittot
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