linux-kernel - Re: [PATCH v8 8/8] rcu/tree: Setschedule gp ktread to SCHED

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Message-ID: <20190702070128.GG26005@localhost.localdomain>
Date:   Tue, 2 Jul 2019 09:01:28 +0200
From:   Juri Lelli <juri.lelli@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     mingo@...hat.com, rostedt@...dmis.org, tj@...nel.org,
        linux-kernel@...r.kernel.org, luca.abeni@...tannapisa.it,
        claudio@...dence.eu.com, tommaso.cucinotta@...tannapisa.it,
        bristot@...hat.com, mathieu.poirier@...aro.org, lizefan@...wei.com,
        cgroups@...r.kernel.org
Subject: Re: [PATCH v8 8/8] rcu/tree: Setschedule gp ktread to SCHED_FIFO
 outside of atomic region

On 01/07/19 21:13, Peter Zijlstra wrote:
> On Fri, Jun 28, 2019 at 10:06:18AM +0200, Juri Lelli wrote:
> > sched_setscheduler() needs to acquire cpuset_rwsem, but it is currently
> > called from an invalid (atomic) context by rcu_spawn_gp_kthread().
> > 
> > Fix that by simply moving sched_setscheduler_nocheck() call outside of
> > the atomic region, as it doesn't actually require to be guarded by
> > rcu_node lock.
> 
> Maybe move this earlier in the series such that the bug doesn't manifest
> in bisection?

OK.