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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id o13sm4083358qtk.12.2020.04.02.09.19.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 02 Apr 2020 09:19:55 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH v2] sched/core: fix illegal RCU from offline CPUs Date: Thu, 2 Apr 2020 12:19:54 -0400 Message-Id: <4134872A-3D1D-4860-9C1B-2FD9C00272BB@lca.pw> References: <20200402155406.GP19865@paulmck-ThinkPad-P72> Cc: Michael Ellerman , Peter Zijlstra , Ingo Molnar , juri.lelli@redhat.com, dietmar.eggemann@arm.com, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, tglx@linutronix.de, "James.Bottomley@hansenpartnership.com" , deller@gmx.de, linuxppc-dev@lists.ozlabs.org, linux-parisc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Nicholas Piggin In-Reply-To: <20200402155406.GP19865@paulmck-ThinkPad-P72> To: paulmck@kernel.org X-Mailer: iPhone Mail (17D50) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > On Apr 2, 2020, at 11:54 AM, Paul E. McKenney wrote: >=20 > I do run this combination quite frequently, but only as part of > rcutorture, which might not be a representative workload. For one thing, > it has a minimal userspace consisting only of a trivial init program. > I don't recall having ever seen this. (I have seen one recent complaint > about an IPI being sent to an offline CPU, but I cannot prove that this > was not due to RCU bugs that I was chasing at the time.) Yes, a trivial init is tough while running systemd should be able to catch i= t as it will use cgroup.=