Re: [PATCH][next] KVM: x86/mmu: Fix uninitialized boolean variable flush

[Paolo Bonzini]

On 22/06/21 17:09, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> In the case where kvm_memslots_have_rmaps(kvm) is false the boolean
> variable flush is not set and is uninitialized.  If is_tdp_mmu_enabled(kvm)
> is true then the call to kvm_tdp_mmu_zap_collapsible_sptes passes the
> uninitialized value of flush into the call. Fix this by initializing
> flush to false.
>
> Addresses-Coverity: ("Uninitialized scalar variable")
> Fixes: e2209710ccc5 ("KVM: x86/mmu: Skip rmap operations if rmaps not allocated")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
>   arch/x86/kvm/mmu/mmu.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index ed24e97c1549..b8d20f139729 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5689,7 +5689,7 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
>   {
>   	/* FIXME: const-ify all uses of struct kvm_memory_slot.  */
>   	struct kvm_memory_slot *slot = (struct kvm_memory_slot *)memslot;
> -	bool flush;
> +	bool flush = false;
>   
>   	if (kvm_memslots_have_rmaps(kvm)) {
>   		write_lock(&kvm->mmu_lock);

Queued, thanks.

Paolo