From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E52D3C433FE for ; Wed, 23 Nov 2022 09:17:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237377AbiKWJRZ (ORCPT ); Wed, 23 Nov 2022 04:17:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237431AbiKWJQ4 (ORCPT ); Wed, 23 Nov 2022 04:16:56 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49BBA107E50 for ; Wed, 23 Nov 2022 01:16:28 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id DD09961B4C for ; Wed, 23 Nov 2022 09:16:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBB28C433D6; Wed, 23 Nov 2022 09:16:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669194987; bh=0EYjDFr7xoTV+UFs7GGOGr0QDiqFY7bNb4GAVBRtLdE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Qh3QyIID3GORr5H6WTooJv20eBRXsJ8XJ0dZc5yLfRnSZ/wMx2WQNKgpo66vqiNIu xTuOfpRI7AbBWzO+kFqefi3sziVXAmWMxFvtaUa5oIJQRYDetTP3nwE6BdxEVOVvUw ZS7iqIqfyycbOju8CRqydcDz0mgoke79/lct7S90= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+9abda841d636d86c41da@syzkaller.appspotmail.com, Takashi Iwai Subject: [PATCH 5.4 115/156] ALSA: usb-audio: Drop snd_BUG_ON() from snd_usbmidi_output_open() Date: Wed, 23 Nov 2022 09:51:12 +0100 Message-Id: <20221123084602.105325784@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084557.816085212@linuxfoundation.org> References: <20221123084557.816085212@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Takashi Iwai commit ad72c3c3f6eb81d2cb189ec71e888316adada5df upstream. snd_usbmidi_output_open() has a check of the NULL port with snd_BUG_ON(). snd_BUG_ON() was used as this shouldn't have happened, but in reality, the NULL port may be seen when the device gives an invalid endpoint setup at the descriptor, hence the driver skips the allocation. That is, the check itself is valid and snd_BUG_ON() should be dropped from there. Otherwise it's confusing as if it were a real bug, as recently syzbot stumbled on it. Reported-by: syzbot+9abda841d636d86c41da@syzkaller.appspotmail.com Cc: Link: https://lore.kernel.org/r/syzbot+9abda841d636d86c41da@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20221112141223.6144-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/usb/midi.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -1149,10 +1149,8 @@ static int snd_usbmidi_output_open(struc port = &umidi->endpoints[i].out->ports[j]; break; } - if (!port) { - snd_BUG(); + if (!port) return -ENXIO; - } substream->runtime->private_data = port; port->state = STATE_UNKNOWN;