Hi Michael,
Thank you for reviewing. I have updated my response inline
On Tue, Feb 13, 2024 at 09:51:30AM +0100, Aiswarya Cyriac wrote:
Fix 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. "
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")
I don't know enough about ALSA to say whether the patch is correct. But the commit log needs work: please, do not "fix warnings" - analyse the code and explain whether there is a real issue and if yes what is it and how it can trigger. Is an invalid op_flag ever passed? If it's just a coverity false positive it might be ok to work around that but document this.
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. I will update the fix and send a v2 patch
sound/virtio/virtio_kctl.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/sound/virtio/virtio_kctl.c b/sound/virtio/virtio_kctl.c index 0c6ac74aca1e..d7a160c5db03 100644 --- a/sound/virtio/virtio_kctl.c +++ b/sound/virtio/virtio_kctl.c @@ -286,6 +286,11 @@ static int virtsnd_kctl_tlv_op(struct snd_kcontrol *kcontrol, int op_flag, else rc = virtsnd_ctl_msg_send(snd, msg, &sg, NULL, false);
break;default:virtsnd_ctl_msg_unref(msg);rc = -EINVAL;
There's already virtsnd_ctl_msg_unref call above. Also don't we need virtsnd_ctl_msg_unref on other error paths such as EFAULT? Unify error handling to fix it all then?
This also need to be handled and virtsnd_ctl_msg_unref needed in case of EFAULT as well. I will update the patch.
Thanks, Aiswarya Cyriac Software Engineer OpenSynergy GmbH Rotherstr. 20, 10245 Berlin
EMail: aiswarya.cyriac@opensynergy.com
www.opensynergy.com Handelsregister/Commercial Registry: Amtsgericht Charlottenburg, HRB 108616B Geschäftsführer/Managing Director: Régis Adjamah
________________________________________ From: Michael S. Tsirkin mst@redhat.com Sent: Tuesday, February 13, 2024 10:06 AM To: Aiswarya Cyriac Cc: jasowang@redhat.com; perex@perex.cz; tiwai@suse.com; linux-kernel@vger.kernel.org; alsa-devel@alsa-project.org; virtualization@lists.linux-foundation.org; virtio-dev@lists.oasis-open.org; Anton Yakovlev; coverity-bot Subject: Re: [PATCH] ALSA: virtio: Fix "Coverity: virtsnd_kctl_tlv_op(): Uninitialized variables" warning.
On Tue, Feb 13, 2024 at 09:51:30AM +0100, Aiswarya Cyriac wrote:
Fix 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. "
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")
I don't know enough about ALSA to say whether the patch is correct. But the commit log needs work: please, do not "fix warnings" - analyse the code and explain whether there is a real issue and if yes what is it and how it can trigger. Is an invalid op_flag ever passed? If it's just a coverity false positive it might be ok to work around that but document this.
sound/virtio/virtio_kctl.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/sound/virtio/virtio_kctl.c b/sound/virtio/virtio_kctl.c index 0c6ac74aca1e..d7a160c5db03 100644 --- a/sound/virtio/virtio_kctl.c +++ b/sound/virtio/virtio_kctl.c @@ -286,6 +286,11 @@ static int virtsnd_kctl_tlv_op(struct snd_kcontrol *kcontrol, int op_flag, else rc = virtsnd_ctl_msg_send(snd, msg, &sg, NULL, false);
break;default:virtsnd_ctl_msg_unref(msg);rc = -EINVAL;
There's already virtsnd_ctl_msg_unref call above. Also don't we need virtsnd_ctl_msg_unref on other error paths such as EFAULT? Unify error handling to fix it all then?
break; }-- 2.43.0