From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: [PATCH] kvm: reset arch memslot info on memslot creation Date: Wed, 10 Jul 2013 11:24:39 +0300 Message-ID: <20130710082439.GA1482@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Gleb Natapov , Paolo Bonzini To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On x86, kvm_arch_create_memslot assumes that rmap/lpage_info for the slot are zeroed out: if they weren't, error handling code after out_free label will free memory which wasn't allocated here. This always happens to be the case because on KVM_MR_DELETE we clear the whole arch structure. So there's no bug, but it's cleaner not to rely on this here. Make the code more robust by clearing the rmap/lpage_info explicitly. Signed-off-by: Michael S. Tsirkin --- arch/x86/kvm/x86.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e8ba99c..96e6eb4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6922,6 +6922,10 @@ int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages) { int i; + /* Reset in case slot had some rmap/lpage_info. */ + memset(&slot->arch.rmap, 0, sizeof slot->arch.rmap); + memset(&slot->arch.lpage_info, 0, sizeof slot->arch.lpage_info); + for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) { unsigned long ugfn; int lpages; -- MST