Re: [PATCH v2] KVM: x86/xen: Fix memory leak in kvm_xen_write_hypercall_page()

[Paul Durrant <xadimgnik@xxxxxxxxx>]

On 20/12/2022 15:14, Michal Luczaj wrote:
> Release page irrespectively of kvm_vcpu_write_guest() return value.
>
> Suggested-by: Paul Durrant <paul@xxxxxxx>
> Fixes: 23200b7a30de ("KVM: x86/xen: intercept xen hypercalls if enabled")
> Signed-off-by: Michal Luczaj <mhal@xxxxxxx>
> ---
>   arch/x86/kvm/xen.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
> index f3098c0e386a..439a65437075 100644
> --- a/arch/x86/kvm/xen.c
> +++ b/arch/x86/kvm/xen.c
> @@ -889,6 +889,7 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
>   		u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
>   				  : kvm->arch.xen_hvm_config.blob_size_32;
>   		u8 *page;
> +		int ret;
>   
>   		if (page_num >= blob_size)
>   			return 1;
> @@ -899,10 +900,10 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
>   		if (IS_ERR(page))
>   			return PTR_ERR(page);
>   
> -		if (kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE)) {
> -			kfree(page);
> +		ret = kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE);
> +		kfree(page);
> +		if (ret)
>   			return 1;
> -		}
>   	}
>   	return 0;
>   }

Thanks.

Reviewed-by: Paul Durrant <paul@xxxxxxx>