From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 5FC976B06BB for ; Thu, 3 Aug 2017 09:18:43 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id r187so12765410pfr.8 for ; Thu, 03 Aug 2017 06:18:43 -0700 (PDT) Received: from mga03.intel.com (mga03.intel.com. [134.134.136.65]) by mx.google.com with ESMTPS id p129si21105681pfp.193.2017.08.03.06.18.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Aug 2017 06:18:42 -0700 (PDT) Message-ID: <59832353.1020600@intel.com> Date: Thu, 03 Aug 2017 21:21:23 +0800 From: Wei Wang MIME-Version: 1.0 Subject: Re: [PATCH v13 5/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ 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> <900253471.38532197.1501765506419.JavaMail.zimbra@redhat.com> In-Reply-To: <900253471.38532197.1501765506419.JavaMail.zimbra@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Pankaj Gupta 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 , mgorman@techsingularity.net, aarcange@redhat.com, amit shah , pbonzini@redhat.com, liliang opensource , yang zhang wz , quan xu On 08/03/2017 09:05 PM, Pankaj Gupta wrote: >> 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? Yes. if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) is true nvqs will be 3, that is, callbacks[2] is allocated. Best, Wei -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org