From fa13843d1565d4c5b3aeb9be3343b313416bef46 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 15 Oct 2021 13:05:00 -0400 Subject: [PATCH] KVM: X86: fix lazy allocation of rmaps If allocation of rmaps fails, but some of the pointers have already been written, those pointers can be cleaned up when the memslot is freed, or even reused later for another attempt at allocating the rmaps. Therefore there is no need to WARN, as done for example in memslot_rmap_alloc, but the allocation *must* be skipped lest KVM will overwrite the previous pointer and will indeed leak memory. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index aabd3a2ec1bc..0c8b5129effd 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11392,7 +11392,8 @@ static int memslot_rmap_alloc(struct kvm_memory_slot *slot, int level = i + 1; int lpages = __kvm_mmu_slot_lpages(slot, npages, level); - WARN_ON(slot->arch.rmap[i]); + if (slot->arch.rmap[i]) + continue; slot->arch.rmap[i] = kvcalloc(lpages, sz, GFP_KERNEL_ACCOUNT); if (!slot->arch.rmap[i]) { -- 2.39.5