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[34.83.123.78]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-39e6c37a88csm6240077a91.8.2026.09.19.15.17.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Sep 2026 15:17:28 -0700 (PDT) From: Hui Peng To: longman@redhat.com, ridong.chen@linux.dev, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] cgroup/cpuset: prevent overlapping local and remote partition creation Date: Sat, 19 Sep 2026 22:17:27 +0000 Message-ID: <20260919221727.3706964-1-benquike@gmail.com> X-Mailer: git-send-email 2.55.0.1082.g2b9226bbc0-goog Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Fix two partition validation bugs in kernel/cgroup/cpuset.c: 1. In remote_partition_enable(), check whether the requested effective xcpus intersect parent->subpartitions_cpus so a remote partition cannot claim CPUs already delegated to a local child partition. 2. In validate_partition(), verify that enabling a local partition does not overlap CPUs already allocated to an active remote partition. Fixes: aa7d3a56a20f ("cpuset: fix warning when disabling remote partition") Assisted-by: LLM Signed-off-by: Hui Peng --- diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 2538faac9aba..13fad096c494 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -713,7 +713,10 @@ static inline bool cpus_excl_conflict(struct cpuset *trial, struct cpuset *sibli return true; /* Exclusive_cpus cannot intersect */ - return cpumask_intersects(trial->exclusive_cpus, sibling->exclusive_cpus); + return cpumask_intersects(trial->exclusive_cpus, + cpumask_empty(sibling->exclusive_cpus) + ? sibling->effective_xcpus + : sibling->exclusive_cpus); } static inline bool mems_excl_conflict(struct cpuset *cs1, struct cpuset *cs2) @@ -1591,8 +1594,8 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, * above it or remote partition root underneath it is not allowed. */ compute_excpus(cs, tmp->new_cpus); - WARN_ON_ONCE(cpumask_intersects(tmp->new_cpus, subpartitions_cpus)); if (!cpumask_intersects(tmp->new_cpus, cpu_active_mask) || + cpumask_intersects(tmp->new_cpus, subpartitions_cpus) || cpumask_subset(top_cpuset.effective_cpus, tmp->new_cpus)) return PERR_INVCPUS; if (((new_prs == PRS_ISOLATED) && @@ -2411,6 +2414,10 @@ static enum prs_errcode validate_partition(struct cpuset *cs, struct cpuset *tri if (cpumask_empty(trialcs->effective_xcpus)) return PERR_INVCPUS; + if ((parent == &top_cpuset) && + cpumask_intersects(trialcs->effective_xcpus, subpartitions_cpus)) + return PERR_REMOTE; + if (prstate_housekeeping_conflict(trialcs->partition_root_state, trialcs->effective_xcpus)) return PERR_HKEEPING; @@ -2970,7 +2977,7 @@ static int update_prstate(struct cpuset *cs, int new_prs) * local or remote partition. */ if ((parent == &top_cpuset) && - cpumask_intersects(cs->exclusive_cpus, subpartitions_cpus)) { + cpumask_intersects(user_xcpus(cs), subpartitions_cpus)) { err = PERR_REMOTE; goto out; }