From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juri Lelli Subject: Re: [PATCH v8 7/8] sched/core: Prevent race condition between cpuset and __sched_setscheduler() Date: Tue, 2 Jul 2019 09:01:12 +0200 Message-ID: <20190702070111.GF26005@localhost.localdomain> References: <20190628080618.522-1-juri.lelli@redhat.com> <20190628080618.522-8-juri.lelli@redhat.com> <20190701191141.GD3402@hirez.programming.kicks-ass.net> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20190701191141.GD3402@hirez.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Peter Zijlstra Cc: mingo@redhat.com, rostedt@goodmis.org, tj@kernel.org, linux-kernel@vger.kernel.org, luca.abeni@santannapisa.it, claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it, bristot@redhat.com, mathieu.poirier@linaro.org, lizefan@huawei.com, cgroups@vger.kernel.org On 01/07/19 21:11, Peter Zijlstra wrote: > On Fri, Jun 28, 2019 at 10:06:17AM +0200, Juri Lelli wrote: > > No synchronisation mechanism exists between the cpuset subsystem and > > calls to function __sched_setscheduler(). As such, it is possible that > > new root domains are created on the cpuset side while a deadline > > acceptance test is carried out in __sched_setscheduler(), leading to a > > potential oversell of CPU bandwidth. > > > > Grab cpuset_rwsem read lock from core scheduler, so to prevent > > situations such as the one described above from happening. > > > > ISTR there being a funny vs normalize_rt_tasks(); maybe mention that? Yep. I'll add a comment about it.