From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from 2.mo177.mail-out.ovh.net ([178.33.109.80]:48833 "EHLO 2.mo177.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751186AbdJLN5C (ORCPT ); Thu, 12 Oct 2017 09:57:02 -0400 Received: from player688.ha.ovh.net (b6.ovh.net [213.186.33.56]) by mo177.mail-out.ovh.net (Postfix) with ESMTP id B851D7C84C for ; Thu, 12 Oct 2017 14:52:11 +0200 (CEST) Date: Thu, 12 Oct 2017 14:51:57 +0200 From: Greg Kurz To: Michael Ellerman Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, Paul Mackerras , stable@vger.kernel.org, Paolo Bonzini , linuxppc-dev@lists.ozlabs.org, Sam Bobroff , David Gibson Subject: Re: [PATCH] KVM: PPC: fix oops when checking KVM_CAP_PPC_HTM Message-ID: <20171012145157.1879b34f@bahia> In-Reply-To: <87wp40txl1.fsf@concordia.ellerman.id.au> References: <150542618501.6859.11512107352972110416.stgit@bahia.lan> <87wp40txl1.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: On Thu, 12 Oct 2017 22:27:54 +1100 Michael Ellerman wrote: > Greg Kurz writes: > > 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; > > Did this go anywhere? > > cheers I'm afraid not... and I haven't tried to ping Paul yet, since he's supposed to be on vacation from what I've been told. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kurz Date: Thu, 12 Oct 2017 12:51:57 +0000 Subject: Re: [PATCH] KVM: PPC: fix oops when checking KVM_CAP_PPC_HTM Message-Id: <20171012145157.1879b34f@bahia> List-Id: References: <150542618501.6859.11512107352972110416.stgit@bahia.lan> <87wp40txl1.fsf@concordia.ellerman.id.au> In-Reply-To: <87wp40txl1.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Michael Ellerman Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, Paul Mackerras , stable@vger.kernel.org, Paolo Bonzini , linuxppc-dev@lists.ozlabs.org, Sam Bobroff , David Gibson On Thu, 12 Oct 2017 22:27:54 +1100 Michael Ellerman wrote: > Greg Kurz writes: > > 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; > > Did this go anywhere? > > cheers I'm afraid not... and I haven't tried to ping Paul yet, since he's supposed to be on vacation from what I've been told.