From: Peter Zijlstra <peterz@infradead.org>
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>,
Tejun Heo <tj@kernel.org>,
"linux-kernel@vger.kernel.org >> Linux Kernel Mailing List"
<linux-kernel@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
KVM list <kvm@vger.kernel.org>, Oleg Nesterov <oleg@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: regression 4.4: deadlock in with cgroup percpu_rwsem
Date: Wed, 20 Jan 2016 11:47:58 +0100 [thread overview]
Message-ID: <20160120104758.GD6373@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160120103036.GJ6357@twins.programming.kicks-ass.net>
On Wed, Jan 20, 2016 at 11:30:36AM +0100, Peter Zijlstra wrote:
> On Wed, Jan 20, 2016 at 11:15:05AM +0100, Christian Borntraeger wrote:
> > [ 561.044066] Krnl PSW : 0704e00180000000 00000000001aa1ee (remove_entity_load_avg+0x1e/0x1b8)
>
> > [ 561.044176] ([<00000000001ad750>] free_fair_sched_group+0x80/0xf8)
> > [ 561.044181] [<0000000000192656>] free_sched_group+0x2e/0x58
> > [ 561.044187] [<00000000001ded82>] rcu_process_callbacks+0x3fa/0x928
>
> Urgh,.. lemme stare at that.
TJ, is css_offline guaranteed to be called in hierarchical order? I
got properly lost in the whole cgroup destroy code. There's endless
workqueues and rcu callbacks there.
So the current place in free_fair_sched_group() is far too late to be
calling remove_entity_load_avg(). But I'm not sure where I should put
it, it needs to be in a place where we know the group is going to die
but its parent is guaranteed to still exist.
Would offline be that place?
next prev parent reply other threads:[~2016-01-20 10:47 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-14 11:19 regression 4.4: deadlock in with cgroup percpu_rwsem Christian Borntraeger
2016-01-14 13:38 ` Christian Borntraeger
2016-01-14 14:04 ` Nikolay Borisov
2016-01-14 14:08 ` Christian Borntraeger
2016-01-14 14:27 ` Nikolay Borisov
2016-01-14 17:15 ` Christian Borntraeger
2016-01-14 19:56 ` Tejun Heo
2016-01-15 7:30 ` Christian Borntraeger
2016-01-15 15:13 ` Christian Borntraeger
2016-01-18 18:32 ` Peter Zijlstra
2016-01-18 18:48 ` Christian Borntraeger
2016-01-19 9:55 ` Heiko Carstens
2016-01-19 19:36 ` Christian Borntraeger
2016-01-19 19:38 ` Tejun Heo
2016-01-20 7:07 ` Heiko Carstens
2016-01-20 10:15 ` Christian Borntraeger
2016-01-20 10:30 ` Peter Zijlstra
2016-01-20 10:47 ` Peter Zijlstra [this message]
2016-01-20 15:30 ` Tejun Heo
2016-01-20 16:04 ` Tejun Heo
2016-01-20 16:49 ` Peter Zijlstra
2016-01-20 16:56 ` Tejun Heo
2016-01-23 2:03 ` Paul E. McKenney
2016-01-25 8:49 ` Christoph Hellwig
2016-01-25 19:38 ` Tejun Heo
2016-01-26 14:51 ` Christoph Hellwig
2016-01-26 15:28 ` Tejun Heo
2016-01-26 16:41 ` Christoph Hellwig
2016-01-20 10:53 ` Peter Zijlstra
2016-01-21 8:23 ` Christian Borntraeger
2016-01-21 9:27 ` Peter Zijlstra
2016-01-15 16:40 ` Tejun Heo
[not found] ` <20160115164023.GH3520-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2016-01-19 17:18 ` [PATCH cgroup/for-4.5-fixes] cpuset: make mm migration asynchronous Tejun Heo
2016-01-19 17:18 ` Tejun Heo
2016-01-22 14:24 ` Christian Borntraeger
2016-01-22 15:22 ` Tejun Heo
[not found] ` <20160122152232.GB32380-piEFEHQLUPpN0TnZuCh8vA@public.gmane.org>
2016-01-22 15:45 ` Christian Borntraeger
2016-01-22 15:45 ` Christian Borntraeger
2016-01-22 15:47 ` Tejun Heo
[not found] ` <20160119171841.GP3520-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2016-01-22 15:23 ` Tejun Heo
2016-01-22 15:23 ` Tejun Heo
[not found] ` <5698A023.9070703-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>
2016-01-21 20:31 ` [PATCH 1/2] cgroup: make sure a parent css isn't offlined before its children Tejun Heo
2016-01-21 20:31 ` Tejun Heo
2016-01-21 20:32 ` [PATCH 2/2] cgroup: make sure a parent css isn't freed " Tejun Heo
2016-01-22 15:45 ` [PATCH v2 " Tejun Heo
2016-01-22 15:45 ` Tejun Heo
[not found] ` <20160121203111.GF5157-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2016-01-21 21:24 ` [PATCH 1/2] cgroup: make sure a parent css isn't offlined " Peter Zijlstra
2016-01-21 21:24 ` Peter Zijlstra
[not found] ` <20160121212416.GL6357-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2016-01-21 21:28 ` Tejun Heo
2016-01-21 21:28 ` Tejun Heo
2016-01-22 8:18 ` Christian Borntraeger
2016-02-29 11:13 ` [tip:sched/core] sched/cgroup: Fix cgroup entity load tracking tear-down tip-bot for Peter Zijlstra
2016-01-22 15:45 ` [PATCH v2 1/2] cgroup: make sure a parent css isn't offlined before its children Tejun Heo
2016-01-22 15:45 ` Tejun Heo
2016-01-22 15:45 ` Tejun Heo
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