Messages in this thread Patch in this message | | | Date | Wed, 10 Jul 2013 11:24:39 +0300 | From | "Michael S. Tsirkin" <> | Subject | [PATCH] kvm: reset arch memslot info on memslot creation |
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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 <mst@redhat.com> --- 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
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