From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from 4.mo2.mail-out.ovh.net ([87.98.172.75]:51738 "EHLO 4.mo2.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453AbdINXP7 (ORCPT ); Thu, 14 Sep 2017 19:15:59 -0400 Received: from player770.ha.ovh.net (b6.ovh.net [213.186.33.56]) by mo2.mail-out.ovh.net (Postfix) with ESMTP id 83458A9A62 for ; Thu, 14 Sep 2017 23:56:34 +0200 (CEST) Subject: [PATCH] KVM: PPC: fix oops when checking KVM_CAP_PPC_HTM From: Greg Kurz To: kvm@vger.kernel.org Cc: kvm-ppc@vger.kernel.org, Paul Mackerras , David Gibson , Sam Bobroff , Paolo Bonzini , linuxppc-dev@lists.ozlabs.org, stable@vger.kernel.org Date: Thu, 14 Sep 2017 23:56:25 +0200 Message-ID: <150542618501.6859.11512107352972110416.stgit@bahia.lan> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: The following program causes a kernel oops: #include #include #include #include #include main() { int fd = open("/dev/kvm", O_RDWR); ioctl(fd, KVM_CHECK_EXTENSION, KVM_CAP_PPC_HTM); } This happens because when using the global KVM fd with KVM_CHECK_EXTENSION, kvm_vm_ioctl_check_extension() gets called with a NULL kvm argument, which gets dereferenced in is_kvmppc_hv_enabled(). Spotted while reading the code. Let's use the hv_enabled fallback variable, like everywhere else in this function. Fixes: 23528bb21ee2 ("KVM: PPC: Introduce KVM_CAP_PPC_HTM") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Greg Kurz --- arch/powerpc/kvm/powerpc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 3480faaf1ef8..ee279c7f4802 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -644,8 +644,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; #endif case KVM_CAP_PPC_HTM: - r = cpu_has_feature(CPU_FTR_TM_COMP) && - is_kvmppc_hv_enabled(kvm); + r = cpu_has_feature(CPU_FTR_TM_COMP) && hv_enabled; break; default: r = 0; From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kurz Date: Thu, 14 Sep 2017 21:56:25 +0000 Subject: [PATCH] KVM: PPC: fix oops when checking KVM_CAP_PPC_HTM Message-Id: <150542618501.6859.11512107352972110416.stgit@bahia.lan> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Cc: kvm-ppc@vger.kernel.org, Paul Mackerras , David Gibson , Sam Bobroff , Paolo Bonzini , linuxppc-dev@lists.ozlabs.org, stable@vger.kernel.org The following program causes a kernel oops: #include #include #include #include #include main() { int fd = open("/dev/kvm", O_RDWR); ioctl(fd, KVM_CHECK_EXTENSION, KVM_CAP_PPC_HTM); } This happens because when using the global KVM fd with KVM_CHECK_EXTENSION, kvm_vm_ioctl_check_extension() gets called with a NULL kvm argument, which gets dereferenced in is_kvmppc_hv_enabled(). Spotted while reading the code. Let's use the hv_enabled fallback variable, like everywhere else in this function. Fixes: 23528bb21ee2 ("KVM: PPC: Introduce KVM_CAP_PPC_HTM") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Greg Kurz --- arch/powerpc/kvm/powerpc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 3480faaf1ef8..ee279c7f4802 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -644,8 +644,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; #endif case KVM_CAP_PPC_HTM: - r = cpu_has_feature(CPU_FTR_TM_COMP) && - is_kvmppc_hv_enabled(kvm); + r = cpu_has_feature(CPU_FTR_TM_COMP) && hv_enabled; break; default: r = 0;