vfio/pci: Fix potential memory leak in vfio_msi_cap_len

BugLink: https://bugs.launchpad.net/bugs/1853881

[ Upstream commit 30ea32ab ]

Free allocated vdev->msi_perm in error path.
Signed-off-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

drivers/vfio/pci/vfio_pci_config.c

@@ -1137,8 +1137,10 @@ static int vfio_msi_cap_len(struct vfio_pci_device *vdev, u8 pos)
 		return -ENOMEM;
 
 	ret = init_pci_cap_msi_perm(vdev->msi_perm, len, flags);
-	if (ret)
+	if (ret) {
+		kfree(vdev->msi_perm);
 		return ret;
+	}
 
 	return len;
 }