diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index b3f972e8cfed6ed69b145c719e852a1beb8209ce..1d3de1ea081df182fdf645f217421707c35b161a 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -254,8 +254,14 @@ static ssize_t sriov_numvfs_show(struct device *dev,
 				 char *buf)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
+	u16 num_vfs;
+
+	/* Serialize vs sriov_numvfs_store() so readers see valid num_VFs */
+	device_lock(&pdev->dev);
+	num_vfs = pdev->sriov->num_VFs;
+	device_unlock(&pdev->dev);
 
-	return sprintf(buf, "%u\n", pdev->sriov->num_VFs);
+	return sprintf(buf, "%u\n", num_vfs);
 }
 
 /*