Re: [PATCH] Using kzalloc to avoid allocating kvm_regs from kernel stack

[Hollis Blanchard <hollisb@us.ibm.com>]

On Mon, 2008-02-25 at 17:34 +0800, Zhang, Xiantao wrote:
> From: Xiantao Zhang <xiantao.zhang@intel.com>
> Date: Mon, 25 Feb 2008 17:11:43 +0800
> Subject: [PATCH] kvm: Using kzalloc to avoid allocating kvm_regs from
> kernel stack.
> 
> Since the size of struct kvm_regs maybe too big to allocate from kernel
> stack,
> here use kzalloc to allocate it.
> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
> ---
>  virt/kvm/kvm_main.c |   15 ++++++++-------
>  1 files changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index cf6df51..5348538 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -806,25 +806,26 @@ static long kvm_vcpu_ioctl(struct file *filp,
>  		r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run);
>  		break;
>  	case KVM_GET_REGS: {
> -		struct kvm_regs kvm_regs;
> +		struct kvm_regs *kvm_regs;
>  
> -		memset(&kvm_regs, 0, sizeof kvm_regs);
> -		r = kvm_arch_vcpu_ioctl_get_regs(vcpu, &kvm_regs);
> +		kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
> +		r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
>  		if (r)
>  			goto out;
>  		r = -EFAULT;
> -		if (copy_to_user(argp, &kvm_regs, sizeof kvm_regs))
> +		if (copy_to_user(argp, kvm_regs, sizeof(struct
> kvm_regs)))
>  			goto out;
>  		r = 0;
>  		break;
>  	}
>  	case KVM_SET_REGS: {
> -		struct kvm_regs kvm_regs;
> +		struct kvm_regs *kvm_regs;
>  
> +		kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
>  		r = -EFAULT;
> -		if (copy_from_user(&kvm_regs, argp, sizeof kvm_regs))
> +		if (copy_from_user(kvm_regs, argp, sizeof(struct
> kvm_regs)))
>  			goto out;
> -		r = kvm_arch_vcpu_ioctl_set_regs(vcpu, &kvm_regs);
> +		r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
>  		if (r)
>  			goto out;
>  		r = 0;

Where is this freed?

-- 
Hollis Blanchard
IBM Linux Technology Center


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