linux-kernel - Re: [PATCH v2] KVM: SVM: Fix potential memory leak in svm_cpu

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Message-ID: <54acb241-9837-ed9c-49a2-976fd6e0ea36@redhat.com>
Date:   Wed, 15 Jan 2020 19:23:59 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linmiaohe <linmiaohe@...wei.com>, rkrcmar@...hat.com,
        sean.j.christopherson@...el.com, vkuznets@...hat.com,
        wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org,
        liran.alon@...cle.com
Subject: Re: [PATCH v2] KVM: SVM: Fix potential memory leak in svm_cpu_init()

On 04/01/20 09:56, linmiaohe wrote:
> From: Miaohe Lin <linmiaohe@...wei.com>
> 
> When kmalloc memory for sd->sev_vmcbs failed, we forget to free the page
> held by sd->save_area. Also get rid of the var r as '-ENOMEM' is actually
> the only possible outcome here.
> 
> Reviewed-by: Liran Alon <liran.alon@...cle.com>
> Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>
> Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
> ---
> -v2:
> 	drop var r as suggested by Vitaly
> ---
>  arch/x86/kvm/svm.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 8f1b715dfde8..5f9d6547e0e7 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -1003,33 +1003,32 @@ static void svm_cpu_uninit(int cpu)
>  static int svm_cpu_init(int cpu)
>  {
>  	struct svm_cpu_data *sd;
> -	int r;
>  
>  	sd = kzalloc(sizeof(struct svm_cpu_data), GFP_KERNEL);
>  	if (!sd)
>  		return -ENOMEM;
>  	sd->cpu = cpu;
> -	r = -ENOMEM;
>  	sd->save_area = alloc_page(GFP_KERNEL);
>  	if (!sd->save_area)
> -		goto err_1;
> +		goto free_cpu_data;
>  
>  	if (svm_sev_enabled()) {
> -		r = -ENOMEM;
>  		sd->sev_vmcbs = kmalloc_array(max_sev_asid + 1,
>  					      sizeof(void *),
>  					      GFP_KERNEL);
>  		if (!sd->sev_vmcbs)
> -			goto err_1;
> +			goto free_save_area;
>  	}
>  
>  	per_cpu(svm_data, cpu) = sd;
>  
>  	return 0;
>  
> -err_1:
> +free_save_area:
> +	__free_page(sd->save_area);
> +free_cpu_data:
>  	kfree(sd);
> -	return r;
> +	return -ENOMEM;
>  
>  }
>  
> 

Queued, thanks.

Paolo