linux-kernel - Re: [PATCH] fix memory leak on kvm_vm_ioctl_create_spapr

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Date:   Tue, 22 Aug 2017 17:15:53 +0200
From:   David Hildenbrand <david@...hat.com>
To:     nixiaoming <nixiaoming@...wei.com>, agraf@...e.com,
        pbonzini@...hat.com, rkrcmar@...hat.com, benh@...nel.crashing.org,
        paulus@...ba.org, mpe@...erman.id.au
Cc:     kvm-ppc@...r.kernel.org, kvm@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fix memory leak on kvm_vm_ioctl_create_spapr_tce

On 22.08.2017 16:28, nixiaoming wrote:
> miss kfree(stt) when anon_inode_getfd return fail
> so add check anon_inode_getfd return val, and kfree stt
> 
> Signed-off-by: nixiaoming <nixiaoming@...wei.com>
> ---
>  arch/powerpc/kvm/book3s_64_vio.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
> index a160c14..a0b4459 100644
> --- a/arch/powerpc/kvm/book3s_64_vio.c
> +++ b/arch/powerpc/kvm/book3s_64_vio.c
> @@ -341,8 +341,11 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
>  
>  	mutex_unlock(&kvm->lock);
>  
> -	return anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
> +	ret = anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
>  				stt, O_RDWR | O_CLOEXEC);
> +	if (ret < 0)
> +		goto fail;
> +	return ret;
>  
>  fail:
>  	if (stt) {
> 


stt has already been added to kvm->arch.spapr_tce_tables, so freeing it
is evil IMHO. I don't know that code, so I don't know if there is some
other place that will make sure that everything in
kvm->arch.spapr_tce_tables will properly get freed, even when no release
function has been called (kvm_spapr_tce_release).
-- 

Thanks,

David