From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 1/2] virtio-balloon: initialize all vq callbacks Date: Wed, 18 Dec 2019 00:19:57 -0500 Message-ID: <20191218001922-mutt-send-email-mst@kernel.org> References: <20191217190610.248061-1-dverkamp@chromium.org> <5DF99A95.8050800@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5DF99A95.8050800@intel.com> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: Wei Wang Cc: virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org On Wed, Dec 18, 2019 at 11:18:45AM +0800, Wei Wang wrote: > On 12/18/2019 03:06 AM, Daniel Verkamp wrote: > > Ensure that elements of the array that correspond to unavailable > > features are set to NULL; previously, they would be left uninitialized. > > > > Since the corresponding names array elements were explicitly set to > > NULL, the uninitialized callback pointers would not actually be > > dereferenced; however, the uninitialized callbacks elements would still > > be read in vp_find_vqs_msix() and used to calculate the number of MSI-X > > vectors required. > > With your 2nd patch: > if (names[i] && callbacks[i]) > ++nvectors; > > It seems this patch isn't necessary as names[i] is already NULL, isn't it? > > Best, > Wei Right but passing uninitialized values isn't nice even if the function called happens to ignore them.