From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pankaj Gupta <pagupta@redhat.com>
Subject: Re: [PATCH v13 5/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ
Date: Thu, 3 Aug 2017 09:05:06 -0400 (EDT)
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References: <1501742299-4369-1-git-send-email-wei.w.wang@intel.com> <1501742299-4369-6-git-send-email-wei.w.wang@intel.com> <147332060.38438527.1501748021126.JavaMail.zimbra@redhat.com> <598316DB.4050308@intel.com>
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Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org,
	kvm@vger.kernel.org, linux-mm@kvack.org, mst@redhat.com,
	mhocko@kernel.org, mawilcox@microsoft.com, akpm@linux-foundation.org,
	virtio-dev@lists.oasis-open.org, david@redhat.com,
	cornelia huck <cornelia.huck@de.ibm.com>,
	mgorman@techsingularity.net, aarcange@redhat.com,
	amit shah <amit.shah@redhat.com>, pbonzini@redhat.com,
	liliang opensource <liliang.opensource@gmail.com>,
	yang zhang wz <yang.zhang.wz@gmail.com>,
	quan xu <quan.xu@aliyun.com>
To: Wei Wang <wei.w.wang@intel.com>
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List-Id: kvm.vger.kernel.org


> 
> On 08/03/2017 04:13 PM, Pankaj Gupta wrote:
> >>
> >> +        /* Allocate space for find_vqs parameters */
> >> +        vqs = kcalloc(nvqs, sizeof(*vqs), GFP_KERNEL);
> >> +        if (!vqs)
> >> +                goto err_vq;
> >> +        callbacks = kmalloc_array(nvqs, sizeof(*callbacks), GFP_KERNEL);
> >> +        if (!callbacks)
> >> +                goto err_callback;
> >> +        names = kmalloc_array(nvqs, sizeof(*names), GFP_KERNEL);
> >                      
> >         is size here (integer) intentional?
> 
> 
> Sorry, I didn't get it. Could you please elaborate more?

This is okay

> 
> 
> >
> >> +        if (!names)
> >> +                goto err_names;
> >> +
> >> +        callbacks[0] = balloon_ack;
> >> +        names[0] = "inflate";
> >> +        callbacks[1] = balloon_ack;
> >> +        names[1] = "deflate";
> >> +
> >> +        i = 2;
> >> +        if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
> >> +                callbacks[i] = stats_request;
> > just thinking if memory for callbacks[3] & names[3] is allocated?
> 
> 
> Yes, the above kmalloc_array allocated them.

I mean we have created callbacks array for two entries 0,1?

callbacks = kmalloc_array(nvqs, sizeof(*callbacks), GFP_KERNEL);

But we are trying to access location '2' which is third:

         i = 2;
+        if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
+                callbacks[i] = stats_request;      <---- callbacks[2]
+                names[i] = "stats";                <----- names[2]
+                i++;
+        }

I am missing anything obvious here?

> 
> 
> Best,
> Wei
> 

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