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Date:   Wed, 31 May 2023 21:13:04 +0300
From:   Dan Carpenter <dan.carpenter@linaro.org>
To:     Simon Horman <simon.horman@corigine.com>
Cc:     Bobby Eshleman <bobby.eshleman@bytedance.com>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        Stefano Garzarella <sgarzare@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Bryan Tan <bryantan@vmware.com>,
        Vishnu Dasa <vdasa@vmware.com>,
        VMware PV-Drivers Reviewers <pv-drivers@vmware.com>,
        kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hyperv@vger.kernel.org
Subject: Re: [PATCH RFC net-next v3 6/8] virtio/vsock: support dgrams
Message-ID: <d2e9c45f-bcbd-4e6a-98c1-c98283450626@kadam.mountain>
References: <20230413-b4-vsock-dgram-v3-0-c2414413ef6a@bytedance.com>
 <20230413-b4-vsock-dgram-v3-6-c2414413ef6a@bytedance.com>
 <ZHdxJxjXDkkO03L4@corigine.com>
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Precedence: bulk

On Wed, May 31, 2023 at 06:09:11PM +0200, Simon Horman wrote:
> > @@ -102,6 +144,7 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
> 
> Smatch that err may not be initialised in the out label below.
> 
> Just above this context the following appears:
> 
> 	if (info->vsk && !skb_set_owner_sk_safe(skb, sk_vsock(info->vsk))) {
> 		WARN_ONCE(1, "failed to allocate skb on vsock socket with sk_refcnt == 0\n");
> 		goto out;
> 	}
> 
> So I wonder if in that case err may not be initialised.
> 

Yep, exactly right.  I commented out the goto and it silenced the
warning.  I also initialized err to zero at the start hoping that it
would trigger a different warning but it didn't.  :(

regards,
dan carpenter


> >  	return skb;
> >  
> >  out:
> > +	*errp = err;
> >  	kfree_skb(skb);
> >  	return NULL;
> >  }