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 372395218A4; Thu, 17 Sep 2026 17:24:50 +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=1789665891; cv=none; b=q4zVLiLbKl3hBupa3lzFdV/jFqf10Nqi56bjg4GT8vlTpQ51tex0hGHQX6kQkQC4kA6yzsCUwYbom0ifPngAJkzOuHiqFWB8DpUgpE9tYz78e65B0sER8mcgDL5ktsAORSRfMGrRj/FmOaK2fhLr9MgdSzFGWv9yT08E3dBevbc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789665891; c=relaxed/simple; bh=0QJrMgF++ghNPndZeR2Z69zARrJz2pkrB378whdfcj8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GcfP3urS1irrVFsp3zXCqadB8Mo3Gs+XsoofWphLZOsFWxJJM5C3O8LWxEVJFFqcM9z3ZKiw578cjnbyrIHypzZNvrLY+jJGSdVtlHVFYxEdH+o43rLF/jt+54o0kMvQFR2UKqNrSRMGIArrF23GYB4+Zm59MadiuS30TL0nQlY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hrHoCNoR; 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="hrHoCNoR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8BC4A1F000FF; Thu, 17 Sep 2026 17:24:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789665890; bh=O4B+vTxoHxNkLYcZqYpUb7OusL2oYlFL8jkgZ8p4YiQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hrHoCNoRilSnBWpsf/iDczuO2kuqt8TO1BcfZkBqUWB6XW/pSLxbuYUwCRvQeDVSZ 21uwOMBFWHORd5Z6MhmXK0+tBUwbwySfkXb+qTcTYLK2lXnvhTEaCh7ErWLjZfRxUO u1pm0X4XA88tgiE9AfryNHsBUfD+1PPaeldHetY0= 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 6.18 0853/1250] virtio_console: do not free control-out buffers on remove Date: Thu, 17 Sep 2026 16:10:48 +0100 Message-ID: <20260917151615.086129693@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151551.901433442@linuxfoundation.org> References: <20260917151551.901433442@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 6.18-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 c355f6d392748..76f934b5d84be 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -1893,13 +1893,28 @@ 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