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Tsirkin" , Eugenio Perez , Takashi Iwai , linux-sound@vger.kernel.org Subject: Re: [PATCH v2 5/5] ALSA: virtio: Keep control payloads alive through DMA completion Date: Tue, 13 Oct 2026 17:59:03 +0900 Message-ID: <179188181241.52451.7572855613839007151@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Thanks, this is a real alignment bug. I reproduced UBSan failures for both the control header and the integer64 response payload with the v2 code. In v3, the alignment is at least __alignof__(struct virtio_snd_ctl_value), in addition to dma_get_cache_alignment(), and the initial +1 offset is removed. Each subsequent region is aligned as well, including when a preceding region has an odd length. The ASan/UBSan regression now checks typed header and 64-bit payload accesses with DMA alignments 1, 2, 4, 8, 32, 64 and 128; v3 passes. The updated series is in the new [PATCH v3 0/5] thread. v3 cover Message-ID: