Date: Wed, 20 Apr 2016 19:53:29 +0200
From: Greg Kurz <gkurz@linux.vnet.ibm.com>
To: Radim =?UTF-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Cc: James Hogan <james.hogan@imgtec.com>, Paolo Bonzini <pbonzini@redhat.com>,
        mingo@redhat.com, linux-mips@linux-mips.org, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, qemu-ppc@nongnu.org,
        Cornelia Huck <cornelia.huck@de.ibm.com>,
        Paul Mackerras <paulus@samba.org>,
        David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH v3] KVM: remove buggy vcpu id check on vcpu creation
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	<20160420170209.GA11071@potion>
	<20160420170924.GA7859@jhogan-linux.le.imgtec.org>
	<20160420172706.GA4044@potion>
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On Wed, 20 Apr 2016 19:27:06 +0200
Radim Krčmář <rkrcmar@redhat.com> wrote:

> 2016-04-20 18:09+0100, James Hogan:
> > On Wed, Apr 20, 2016 at 07:02:10PM +0200, Radim Krčmář wrote:  
> >> 2016-04-20 17:44+0200, Greg Kurz:  
> >> > diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
> >> > index 70ef1a43c114..0278ea146db5 100644
> >> > --- a/arch/mips/kvm/mips.c
> >> > +++ b/arch/mips/kvm/mips.c
> >> > @@ -248,9 +248,14 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
> >> >  	int err, size, offset;
> >> >  	void *gebase;
> >> >  	int i;
> >> > +	struct kvm_vcpu *vcpu;
> >> >  
> >> > -	struct kvm_vcpu *vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL);
> >> > +	if (id >= KVM_MAX_VCPUS) {
> >> > +		err = -EINVAL;
> >> > +		goto out;  
> >> 
> >> 'vcpu' looks undefined at this point, so kfree in 'out:' may bug.  
> > 
> > Thats out_free_cpu I think?  
> 
> My bad, it is.  Thank you!
> 

I kept the goto based construct because it was done this way for kzalloc().
but I agree that 'return ERR_PTR(-EINVAL)' may look more explicit.

Worth a v4 ?

Cheers.

--
Greg