[v3 PATCH] ALSA: virtio: Fix "Coverity: virtsnd_kctl_tlv_op(): Uninitialized variables" warning.
From: Aiswarya Cyriac
Date: Wed Feb 14 2024 - 09:02:04 EST
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@xxxxxxxxxxxxxxx>
Signed-off-by: Aiswarya Cyriac <aiswarya.cyriac@xxxxxxxxxxxxxxx>
Reported-by: coverity-bot <keescook+coverity-bot@xxxxxxxxxxxx>
Addresses-Coverity-ID: 1583619 ("Uninitialized variables")
Fixes: d6568e3de42d ("ALSA: virtio: add support for audio controls")
---
sound/virtio/virtio_kctl.c | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)
diff --git a/sound/virtio/virtio_kctl.c b/sound/virtio/virtio_kctl.c
index 0c6ac74aca1e..40606eb381af 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_cleanup;
}
sg_init_one(&sg, tlv, size);
@@ -266,6 +266,11 @@ static int virtsnd_kctl_tlv_op(struct snd_kcontrol *kcontrol, int op_flag,
case SNDRV_CTL_TLV_OP_READ:
hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_TLV_READ);
+ /* Since virtsnd_ctl_msg_send() drops the reference, we increase
+ * the counter to be consistent with the on_cleanup path.
+ */
+ virtsnd_ctl_msg_ref(msg);
+
rc = virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
if (!rc) {
if (copy_to_user(utlv, tlv, size))
@@ -281,14 +286,26 @@ 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
+ } else {
+ /* Same as the comment above */
+ virtsnd_ctl_msg_ref(msg);
+
rc = virtsnd_ctl_msg_send(snd, msg, &sg, NULL, false);
+ }
+
+ break;
+ default:
+ rc = -EINVAL;
+ WARN_ON(1);
break;
}
+on_cleanup:
+ virtsnd_ctl_msg_unref(msg);
+
kfree(tlv);
return rc;
--
2.43.0