Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C8833DB62F; Thu, 17 Sep 2026 18:43:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789670600; cv=none; b=kAPB37Yh6zpZTDDRhpcbdyUkX5+ChSVq/hJr8aNEt1MVdaaavTwPec4LZ5MedQLkKhmBN70ivQaVtBVVUsLXptVlRoM8mvyPVJXRVRQTcD6JtMFAVsBOEe5/uCdq2fg3PCMkhWzpjD9jNPJlZrh66HpxaWI4hytXnuT42i02aGI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789670600; c=relaxed/simple; bh=cW/ERb4v5m21Y2Z9DXTPZqdUt7RVOrYkT0O1SE32/cI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L50fISsNlQUtCljd3FO2kIDGX32w13Eey9gnA6LRtsauWWNd+XCkh1MIMz74XI1WKr0whPuCNcFTPVOrmede2JxWqa6Lz/5eZ7P8zkERItb8l6zIu8AaQnivqpVMaLjqmilp7Qa6ab/LGWf+H9/rTy8l5QgCZfD7pHsK552d0fg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TM86tNHB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TM86tNHB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9DE501F000FF; Thu, 17 Sep 2026 18:43:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789670598; bh=rrm1bFGQvFmgERa+XPXuFYj6NKxdkAb9teJrD4EP0vU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TM86tNHBP4r5hk8zLawJap/CSfcjyqc1BuNunXPjS1X3DzF7UxqZfWi2hBlmzYX+p Kn1wjfW+ppX6nzHhlFWtfvjehFFJQcltKzXhFUFjimGKKbgo2nCg4PmFajWk7vG+MY iPhTP3uGuoS6TnscFnH601KFREQubbn0agmxciJ8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jia Jia , "Michael S. Tsirkin" , Sasha Levin Subject: [PATCH 6.12 0712/1102] virtio_console: do not free control-out buffers on remove Date: Thu, 17 Sep 2026 16:10:55 +0100 Message-ID: <20260917151558.206539400@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151539.408551884@linuxfoundation.org> References: <20260917151539.408551884@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jia Jia [ Upstream commit 894f98e73983f37354214a89a3a7fd35bf9e3072 ] __send_control_msg() publishes &portdev->cpkt as the control-out virtqueue cookie. remove_vqs() walks every virtqueue and passes leftover cookies to free_buf(), which treats them as struct port_buffer and reads sgpages. If a control message is still on c_ovq when the device is unbound, free_buf() reads past the ports_device object. KASAN reported slab-out-of-bounds in free_buf(): free_buf remove_vqs virtcons_remove unbind_store The object was the ports_device allocated in virtcons_probe(). Drain c_ovq without freeing. The packet lives in portdev and is released with it. Fixes: a7a69ec0d8e4 ("virtio_console: free buffers after reset") Signed-off-by: Jia Jia Signed-off-by: Michael S. Tsirkin Message-ID: <20260819021230.292696-1-physicalmtea@gmail.com> Signed-off-by: Sasha Levin --- drivers/char/virtio_console.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 8765e8fcb68a7..75ba23fa2187b 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -1896,13 +1896,28 @@ static const struct file_operations portdev_fops = { static void remove_vqs(struct ports_device *portdev) { struct virtqueue *vq; + bool multiport = use_multiport(portdev); virtio_device_for_each_vq(portdev->vdev, vq) { struct port_buffer *buf; + unsigned int len; - flush_bufs(vq, true); - while ((buf = virtqueue_detach_unused_buf(vq))) - free_buf(buf, true); + /* + * c_ovq cookies are &portdev->cpkt, not port_buffer. + * Detach them but do not free_buf(). + */ + if (multiport && vq == portdev->c_ovq) { + spin_lock(&portdev->c_ovq_lock); + while (virtqueue_get_buf(vq, &len)) + ; + while (virtqueue_detach_unused_buf(vq)) + ; + spin_unlock(&portdev->c_ovq_lock); + } else { + flush_bufs(vq, true); + while ((buf = virtqueue_detach_unused_buf(vq))) + free_buf(buf, true); + } cond_resched(); } portdev->vdev->config->del_vqs(portdev->vdev); -- 2.53.0