From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-242.mta1.migadu.com [95.215.58.242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E2B1C511207 for ; Tue, 29 Sep 2026 10:28:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.242 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790677751; cv=none; b=AvvkWcoWq1XW+HoGqrx9g5O+gTCMZx+Y4Sk1V+EZ+qirEOOwNboaKzwAsqTR3rZVdKoUAIJp7ET1AtHg+nzcSSUdrmRwEnXwKe7fV6PZ9+z+2rXk9yU90ZE7u/Szs7Lmxv0mpufq0CavIyheNwrF/1gHPjI09naYB3Pu93MVOzo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790677751; c=relaxed/simple; bh=pD+cis/wDWCh93w5eb5Uib3ul/Qyk4R+r1GaHe1/vbA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cPz/RLZWFGncqobd2GcUDjak/pyYFGZqgae1r1UpPCDDSZrXSGOI7AHtUY7KKqNFHgDalIwyL0Sm5SAkwc5QnuePQFM/ungJodpieyanEKLPH4FKTZcAULsQy7vuDJK/SUmS3xymm2iaSiQg0Lq/wMmmSqpxiVhxYKH6WzSG2x8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ErmKEZm6; arc=none smtp.client-ip=95.215.58.242 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ErmKEZm6" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=pD+cis/wDWCh93w5eb5Uib3ul/Qyk4R+r1GaHe1/vbA=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790677727; v=1; x=1791282527; b=ErmKEZm6fD7msYX/LvY2lNTjDlK/Ff5NTSJyjpLx3MCeWRdKheMo2koufaXJTji48czHASqy itIZsaJKIX6XSg+dPaHoHDCh24IV44k5q1eg6rnRRkEaUh0eJYqYOGMH1IJfvcG5UotNscXwPG8 9PEwis2f8XVMJRZ10UzK4NTI= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 9fbbb2095db56e44; Tue, 29 Sep 2026 10:28:47 +0000 X-Mizu-Trace-ID: 9fbbb2095db56e44 X-Migadu-Flow: FLOW_OUT From: Tao Cui To: maobibo@loongson.cn, gaosong@loongson.cn, zhaotianrui@loongson.cn Cc: loongarch@lists.linux.dev, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, chenhuacai@kernel.org, kernel@xen0n.name, nagachaithanya9911@gmail.com, cui.tao@linux.dev, Tao Cui Subject: [PATCH v2 2/4] LoongArch: KVM: Load dmsintc pointer once in pch_msi_set_irq Date: Tue, 29 Sep 2026 18:28:19 +0800 Message-ID: <20260929102821.36112-3-cui.tao@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260929102821.36112-1-cui.tao@linux.dev> References: <20260929102821.36112-1-cui.tao@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tao Cui pch_msi_set_irq() reads kvm->arch.dmsintc several times: the non-NULL check and the address-window comparison each reload the pointer, so a concurrent device removal can be observed between them and the following dereference hits a freed object. Load the pointer once at the top of pch_msi_set_irq() and add a NULL check with a local snapshot in dmsintc_set_irq(). Both loads use READ_ONCE() so the compiler keeps them single. This closes the reload race; a narrower window where removal happens right after the load remains, as the injection path takes no lock against destroy. Fixes: 03de5eecb0f0 ("LoongArch: KVM: Add DMSINTC inject msi to vCPU") Signed-off-by: Tao Cui --- arch/loongarch/kvm/intc/dmsintc.c | 6 +++++- arch/loongarch/kvm/intc/pch_pic.c | 7 ++++--- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/loongarch/kvm/intc/dmsintc.c b/arch/loongarch/kvm/intc/dmsintc.c index 41c8b597b5bd..91a163698c3c 100644 --- a/arch/loongarch/kvm/intc/dmsintc.c +++ b/arch/loongarch/kvm/intc/dmsintc.c @@ -69,9 +69,13 @@ int dmsintc_set_irq(struct kvm *kvm, u64 addr, int data, int level) { unsigned int irq, cpu; struct kvm_vcpu *vcpu; + struct loongarch_dmsintc *s = READ_ONCE(kvm->arch.dmsintc); + + if (!s) + return -EINVAL; irq = (addr >> AVEC_IRQ_SHIFT) & AVEC_IRQ_MASK; - cpu = (addr >> AVEC_CPU_SHIFT) & kvm->arch.dmsintc->cpu_mask; + cpu = (addr >> AVEC_CPU_SHIFT) & s->cpu_mask; if (cpu >= KVM_MAX_VCPUS) return -EINVAL; vcpu = kvm_get_vcpu_by_cpuid(kvm, cpu); diff --git a/arch/loongarch/kvm/intc/pch_pic.c b/arch/loongarch/kvm/intc/pch_pic.c index 62c09b5f3937..30a8c65c7609 100644 --- a/arch/loongarch/kvm/intc/pch_pic.c +++ b/arch/loongarch/kvm/intc/pch_pic.c @@ -71,10 +71,11 @@ void pch_pic_set_irq(struct loongarch_pch_pic *s, int irq, int level) int pch_msi_set_irq(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e, int level) { u64 msg_addr = (((u64)e->msi.address_hi) << 32) | e->msi.address_lo; + struct loongarch_dmsintc *dmsintc = READ_ONCE(kvm->arch.dmsintc); - if (cpu_has_msgint && kvm->arch.dmsintc && - msg_addr >= kvm->arch.dmsintc->msg_addr_base && - msg_addr < (kvm->arch.dmsintc->msg_addr_base + kvm->arch.dmsintc->msg_addr_size)) { + if (cpu_has_msgint && dmsintc && + msg_addr >= dmsintc->msg_addr_base && + msg_addr < (dmsintc->msg_addr_base + dmsintc->msg_addr_size)) { return dmsintc_set_irq(kvm, msg_addr, e->msi.data, level); } -- 2.43.0