From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tejun Heo <tj@kernel.org>, "x86@kernel.org" <x86@kernel.org>,
"mingo@elte.hu" <mingo@elte.hu>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] stop_machine: kill __stop_machine()
Date: Thu, 16 Jun 2011 20:28:17 +0200 [thread overview]
Message-ID: <1308248897.13240.272.camel@twins> (raw)
In-Reply-To: <1308248260.2682.413.camel@sbsiddha-MOBL3.sc.intel.com>
On Thu, 2011-06-16 at 11:17 -0700, Suresh Siddha wrote:
> > > Peter, So it looks like we are allowing a new cpu to come online in
> > > parallel, while we poke the text? Isn't it a problem? What am I missing?
> >
> > the caller already did get_online_cpus(),
> >
> > do_optimize_kprobes()
> > get_online_cpus()
> > arch_optimize_kprobes()
> > text_poke_smp_batch()
> > put_online_cpus()
>
> So the circular dependency reported is not possible in practice right?
why not? get_online_cpus() takes a mutex, that connects smp_alt and
text_mutex and can cause a deadlock.
next prev parent reply other threads:[~2011-06-16 18:28 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-14 17:06 [PATCHSET] stop_machine: implement stop_machine_from_offline_cpu() Tejun Heo
2011-06-14 17:06 ` [PATCH 1/3] stop_machine: kill __stop_machine() Tejun Heo
2011-06-16 12:12 ` Peter Zijlstra
2011-06-16 12:44 ` Tejun Heo
2011-06-16 17:37 ` Suresh Siddha
2011-06-16 17:55 ` Peter Zijlstra
2011-06-16 18:17 ` Suresh Siddha
2011-06-16 18:28 ` Tejun Heo
2011-06-16 18:36 ` Peter Zijlstra
2011-06-16 18:44 ` Suresh Siddha
2011-06-16 18:28 ` Peter Zijlstra [this message]
2011-06-14 17:06 ` [PATCH 2/3] stop_machine: reorganize stop_cpus() implementation Tejun Heo
2011-06-14 17:06 ` [PATCH 3/3] stop_machine: implement stop_machine_from_offline_cpu() Tejun Heo
2011-06-16 12:10 ` [PATCHSET] " Peter Zijlstra
2011-06-16 12:15 ` Tejun Heo
2011-06-16 17:21 ` Suresh Siddha
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