Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio fixes from Michael Tsirkin:
 "Fixes to multiple issues in virtio.

  Most notably a regression fix for crashes reported by Fedora users.
  Hibernate is still reportedly broken, working on it"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_balloon: prevent uninitialized variable use
  virtio-balloon: use actual number of stats for stats queue buffers
  virtio_balloon: init 1st buffer in stats vq
  virtio_pci: fix out of bound access for msix_names

Author: torvalds

drivers/virtio/virtio_balloon.c

@@ -242,30 +242,34 @@ static inline void update_stat(struct virtio_balloon *vb, int idx,
 
 #define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT)
 
-static void update_balloon_stats(struct virtio_balloon *vb)
+static unsigned int update_balloon_stats(struct virtio_balloon *vb)
 {
 	unsigned long events[NR_VM_EVENT_ITEMS];
 	struct sysinfo i;
-	int idx = 0;
+	unsigned int idx = 0;
 	long available;
 
 	all_vm_events(events);
 	si_meminfo(&i);
 
 	available = si_mem_available();
 
+#ifdef CONFIG_VM_EVENT_COUNTERS
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
 				pages_to_bytes(events[PSWPIN]));
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT,
 				pages_to_bytes(events[PSWPOUT]));
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]);
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]);
+#endif
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE,
 				pages_to_bytes(i.freeram));
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT,
 				pages_to_bytes(i.totalram));
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_AVAIL,
 				pages_to_bytes(available));
+
+	return idx;
 }
 
 /*
@@ -291,14 +295,14 @@ static void stats_handle_request(struct virtio_balloon *vb)
 {
 	struct virtqueue *vq;
 	struct scatterlist sg;
-	unsigned int len;
+	unsigned int len, num_stats;
 
-	update_balloon_stats(vb);
+	num_stats = update_balloon_stats(vb);
 
 	vq = vb->stats_vq;
 	if (!virtqueue_get_buf(vq, &len))
 		return;
-	sg_init_one(&sg, vb->stats, sizeof(vb->stats));
+	sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats);
 	virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL);
 	virtqueue_kick(vq);
 }
@@ -423,13 +427,16 @@ static int init_vqs(struct virtio_balloon *vb)
 	vb->deflate_vq = vqs[1];
 	if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
 		struct scatterlist sg;
+		unsigned int num_stats;
 		vb->stats_vq = vqs[2];
 
 		/*
 		 * Prime this virtqueue with one buffer so the hypervisor can
 		 * use it to signal us later (it can't be broken yet!).
 		 */
-		sg_init_one(&sg, vb->stats, sizeof vb->stats);
+		num_stats = update_balloon_stats(vb);
+
+		sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats);
 		if (virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, GFP_KERNEL)
 		    < 0)
 			BUG();

drivers/virtio/virtio_pci_common.c

@@ -147,7 +147,7 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	const char *name = dev_name(&vp_dev->vdev.dev);
-	int i, err = -ENOMEM, allocated_vectors, nvectors;
+	int i, j, err = -ENOMEM, allocated_vectors, nvectors;
 	unsigned flags = PCI_IRQ_MSIX;
 	bool shared = false;
 	u16 msix_vec;
@@ -212,7 +212,7 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
 	if (!vp_dev->msix_vector_map)
 		goto out_disable_config_irq;
 
-	allocated_vectors = 1; /* vector 0 is the config interrupt */
+	allocated_vectors = j = 1; /* vector 0 is the config interrupt */
 	for (i = 0; i < nvqs; ++i) {
 		if (!names[i]) {
 			vqs[i] = NULL;
@@ -236,18 +236,19 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
 			continue;
 		}
 
-		snprintf(vp_dev->msix_names[i + 1],
+		snprintf(vp_dev->msix_names[j],
 			 sizeof(*vp_dev->msix_names), "%s-%s",
 			 dev_name(&vp_dev->vdev.dev), names[i]);
 		err = request_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec),
 				  vring_interrupt, IRQF_SHARED,
-				  vp_dev->msix_names[i + 1], vqs[i]);
+				  vp_dev->msix_names[j], vqs[i]);
 		if (err) {
 			/* don't free this irq on error */
 			vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR;
 			goto out_remove_vqs;
 		}
 		vp_dev->msix_vector_map[i] = msix_vec;
+		j++;
 
 		/*
 		 * Use a different vector for each queue if they are available,