On Fri, Feb 16, 2024 at 11:06:43AM +0100, Aiswarya Cyriac wrote:
This commit fixes the following warning when building virtio_snd driver.
" *** CID 1583619: Uninitialized variables (UNINIT) sound/virtio/virtio_kctl.c:294 in virtsnd_kctl_tlv_op() 288 289 break; 290 } 291 292 kfree(tlv); 293 vvv CID 1583619: Uninitialized variables (UNINIT) vvv Using uninitialized value "rc". 294 return rc; 295 } 296 297 /** 298 * virtsnd_kctl_get_enum_items() - Query items for the ENUMERATED element type. 299 * @snd: VirtIO sound device. "
This warning is caused by the absence of the "default" branch in the switch-block, and is a false positive because the kernel calls virtsnd_kctl_tlv_op() only with values for op_flag processed in this block.
Also, this commit unifies the cleanup path for all possible control paths in the callback function.
Signed-off-by: Anton Yakovlev anton.yakovlev@opensynergy.com Signed-off-by: Aiswarya Cyriac aiswarya.cyriac@opensynergy.com Reported-by: coverity-bot keescook+coverity-bot@chromium.org Addresses-Coverity-ID: 1583619 ("Uninitialized variables") Fixes: d6568e3de42d ("ALSA: virtio: add support for audio controls")
sound/virtio/virtio_kctl.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/sound/virtio/virtio_kctl.c b/sound/virtio/virtio_kctl.c index 0c6ac74aca1e..7aa79c05b464 100644 --- a/sound/virtio/virtio_kctl.c +++ b/sound/virtio/virtio_kctl.c @@ -253,8 +253,8 @@ static int virtsnd_kctl_tlv_op(struct snd_kcontrol *kcontrol, int op_flag,
tlv = kzalloc(size, GFP_KERNEL); if (!tlv) {
virtsnd_ctl_msg_unref(msg);return -ENOMEM;
rc = -ENOMEM;goto on_msg_unref;}
sg_init_one(&sg, tlv, size);
@@ -281,14 +281,25 @@ static int virtsnd_kctl_tlv_op(struct snd_kcontrol *kcontrol, int op_flag, hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_TLV_COMMAND);
if (copy_from_user(tlv, utlv, size))
if (copy_from_user(tlv, utlv, size)) { rc = -EFAULT;
else
goto on_msg_unref;} else { rc = virtsnd_ctl_msg_send(snd, msg, &sg, NULL, false);}break;
default:
rc = -EINVAL;/* We never get here - we listed all values for op_flag */WARN_ON(1);goto on_msg_unref;}
kfree(tlv);
return rc;
+on_msg_unref:
virtsnd_ctl_msg_unref(msg); kfree(tlv);
return rc;
I don't really like adding code for a false-positive but ALSA maintainers seem to like this. If yes, this seems like as good a way as any to do it.
Acked-by: Michael S. Tsirkin mst@redhat.com
-- 2.43.2