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d=suse.de; s=susede2_ed25519; t=1707910668; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kxIyYzxOV3nh9HraFjdth4tMMfmT9KWuLu4edl2ED40=; b=Td7Ix7OGyXKKX8V/QjHkw3TVNKRaQkjIY821twbMc+JKTREmDRSUlv0oMBcXc8aIMLlzY4 kFyHx1Sbeu/xX0Dg== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id B705613A6D; Wed, 14 Feb 2024 11:37:47 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap1.dmz-prg2.suse.org with ESMTPSA id BBhGKwumzGUiXAAAD6G6ig (envelope-from ); Wed, 14 Feb 2024 11:37:47 +0000 Date: Wed, 14 Feb 2024 12:37:47 +0100 Message-ID: <871q9fi8dw.wl-tiwai@suse.de> From: Takashi Iwai To: "Michael S. Tsirkin" Cc: Aiswarya Cyriac , "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 , Mikhail Golubev-Ciuchea Subject: Re: [PATCH] ALSA: virtio: Fix "Coverity: virtsnd_kctl_tlv_op(): Uninitialized variables" warning. In-Reply-To: <20240214062348-mutt-send-email-mst@kernel.org> References: <20240213085131.503569-1-aiswarya.cyriac@opensynergy.com> <20240213035806-mutt-send-email-mst@kernel.org> <20240214062348-mutt-send-email-mst@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=RJWwqUfN; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=Td7Ix7OG X-Spamd-Result: default: False [-1.81 / 50.00]; ARC_NA(0.00)[]; TO_DN_EQ_ADDR_SOME(0.00)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; BAYES_HAM(-3.00)[100.00%]; TAGGED_RCPT(0.00)[coverity-bot]; MIME_GOOD(-0.10)[text/plain]; DWL_DNSWL_LOW(-1.00)[suse.de:dkim]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DKIM_TRACE(0.00)[suse.de:+]; MX_GOOD(-0.01)[]; RCPT_COUNT_TWELVE(0.00)[12]; MID_CONTAINS_FROM(1.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim,opensynergy.com:email]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_ALL(0.00)[]; SUSPICIOUS_RECIPS(1.50)[] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: 1C88E1F7F5 On Wed, 14 Feb 2024 12:30:19 +0100, Michael S. Tsirkin wrote: > > On Wed, Feb 14, 2024 at 09:08:26AM +0000, Aiswarya Cyriac wrote: > > 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 > > >> Signed-off-by: Aiswarya Cyriac > > >> Reported-by: coverity-bot > > >> 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. > > Well we don't normally have functions validate inputs. > In this case I am not really sure we should bother > with adding dead code. If you really want to, add BUG_ON. Please don't use BUG_ON() in such a case... There is no reason to break the whole operation. thanks, Takashi