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Sat, 16 May 2020 01:22:38 -0700 (PDT) From: madhuparnabhowmik10@gmail.com To: pbonzini@redhat.com, sean.j.christopherson@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, tglx@linutronix.de, bp@alien8.de Date: Sat, 16 May 2020 13:52:27 +0530 Message-Id: <20200516082227.22194-1-madhuparnabhowmik10@gmail.com> X-Mailer: git-send-email 2.17.1 Cc: kvm@vger.kernel.org, paulmck@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Madhuparna Bhowmik , joel@joelfernandes.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: [Linux-kernel-mentees] [PATCH v2] kvm: Fix false positive RCU usage warning X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" From: Madhuparna Bhowmik Fix the following false positive warnings: [ 9403.765413][T61744] ============================= [ 9403.786541][T61744] WARNING: suspicious RCU usage [ 9403.807865][T61744] 5.7.0-rc1-next-20200417 #4 Tainted: G L [ 9403.838945][T61744] ----------------------------- [ 9403.860099][T61744] arch/x86/kvm/mmu/page_track.c:257 RCU-list traversed in non-reader section!! and [ 9405.859252][T61751] ============================= [ 9405.859258][T61751] WARNING: suspicious RCU usage [ 9405.880867][T61755] ----------------------------- [ 9405.911936][T61751] 5.7.0-rc1-next-20200417 #4 Tainted: G L [ 9405.911942][T61751] ----------------------------- [ 9405.911950][T61751] arch/x86/kvm/mmu/page_track.c:232 RCU-list traversed in non-reader section!! Since srcu read lock is held, these are false positive warnings. Therefore, pass condition srcu_read_lock_held() to list_for_each_entry_rcu(). Reported-by: kernel test robot Signed-off-by: Madhuparna Bhowmik --- v2: -Rebase v5.7-rc5 arch/x86/kvm/mmu/page_track.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c index ddc1ec3bdacd..1ad79c7aa05b 100644 --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -229,7 +229,8 @@ void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, return; idx = srcu_read_lock(&head->track_srcu); - hlist_for_each_entry_rcu(n, &head->track_notifier_list, node) + hlist_for_each_entry_rcu(n, &head->track_notifier_list, node, + srcu_read_lock_held(&head->track_srcu)) if (n->track_write) n->track_write(vcpu, gpa, new, bytes, n); srcu_read_unlock(&head->track_srcu, idx); @@ -254,7 +255,8 @@ void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot) return; idx = srcu_read_lock(&head->track_srcu); - hlist_for_each_entry_rcu(n, &head->track_notifier_list, node) + hlist_for_each_entry_rcu(n, &head->track_notifier_list, node, + srcu_read_lock_held(&head->track_srcu)) if (n->track_flush_slot) n->track_flush_slot(kvm, slot, n); srcu_read_unlock(&head->track_srcu, idx); -- 2.17.1 _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees