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[35.130.123.74]) by smtp.gmail.com with ESMTPSA id 00721157ae682-7fd28ce0853sm60479977b3.34.2026.06.17.21.21.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Jun 2026 21:21:51 -0700 (PDT) From: Yury Norov X-Google-Original-From: Yury Norov Date: Thu, 18 Jun 2026 00:21:50 -0400 To: Shrikanth Hegde Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, yury.norov@gmail.com, kprateek.nayak@amd.com, iii@linux.ibm.com, tglx@kernel.org, gregkh@linuxfoundation.org, pbonzini@redhat.com, seanjc@google.com, vschneid@redhat.com, huschle@linux.ibm.com, rostedt@goodmis.org, dietmar.eggemann@arm.com, mgorman@suse.de, bsegall@google.com, maddy@linux.ibm.com, srikar@linux.ibm.com, hdanton@sina.com, chleroy@kernel.org, vineeth@bitbyteword.org, frederic@kernel.org, arighi@nvidia.com, pauld@redhat.com, christian.loehle@arm.com, tj@kernel.org, tommaso.cucinotta@gmail.com, maz@kernel.org, rafael@kernel.org Subject: Re: [PATCH v4 20/20] sched/core: Add a few check for valid CPU in inc/dec of preferred CPUs Message-ID: References: <20260617174139.155540-1-sshegde@linux.ibm.com> <20260617174139.155540-21-sshegde@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260617174139.155540-21-sshegde@linux.ibm.com> On Wed, Jun 17, 2026 at 11:11:39PM +0530, Shrikanth Hegde wrote: > Add few cpumask_check where cpu is expected to be a a valid one. This should be embedded in the corresponding patches, no need to make it a separate patch. > Signed-off-by: Shrikanth Hegde > --- > v3->v4: > - new patch. > > kernel/sched/core.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 57d52973ef0d..9342aae315ca 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -11417,6 +11417,9 @@ void arch_dec_preferred_cpus(struct steal_monitor_t *sm, u64 steal_ratio) > > last_cpu = cpumask_last(cpu_preferred_mask); > > + /* mask can't be null */ > + cpumask_check(last_cpu); cpumask_check() is disabled by default. If you need to enforce the code, use WARN_ON(). > + > /* > * If the core belongs to the housekeeping CPUs, no action is > * taken. This leaves at least one core preferred always. > @@ -11505,6 +11508,9 @@ void sched_trigger_steal_computation(int cpu) > cpu_active_mask); > ktime_t now; > > + /* at least one housekeeping CPU must be active */ > + cpumask_check(first_hk_cpu); > + > /* Done by first active housekeeping CPU only */ > if (likely(cpu != first_hk_cpu)) > return; > -- > 2.47.3