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 X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A64AC433E0 for ; Fri, 7 Aug 2020 08:04:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BA1020866 for ; Fri, 7 Aug 2020 08:04:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726664AbgHGIEo (ORCPT ); Fri, 7 Aug 2020 04:04:44 -0400 Received: from mx2.suse.de ([195.135.220.15]:44012 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725805AbgHGIEo (ORCPT ); Fri, 7 Aug 2020 04:04:44 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C8921AB7D; Fri, 7 Aug 2020 08:05:00 +0000 (UTC) Date: Fri, 07 Aug 2020 10:04:41 +0200 Message-ID: From: Takashi Iwai To: Dinghao Liu Cc: kjlu@umn.edu, Jaroslav Kysela , Takashi Iwai , "Geoffrey D. Bennett" , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ALSA: usb-audio: Fix memleak in scarlett2_add_new_ctl In-Reply-To: <20200807071229.9533-1-dinghao.liu@zju.edu.cn> References: <20200807071229.9533-1-dinghao.liu@zju.edu.cn> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 07 Aug 2020 09:12:27 +0200, Dinghao Liu wrote: > > When snd_usb_mixer_add_control() fails, elem needs to be > freed just like when snd_ctl_new1() fails. However, current > code is returning directly and ends up leaking memory. No, this would lead to double-free. snd_ctl_add() shows a kind of special behavior, it already releases the object at its error path. thanks, Takashi > > Fixes: 9e4d5c1be21f0 ("ALSA: usb-audio: Scarlett Gen 2 mixer interface") > Signed-off-by: Dinghao Liu > --- > sound/usb/mixer_scarlett_gen2.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/sound/usb/mixer_scarlett_gen2.c b/sound/usb/mixer_scarlett_gen2.c > index 74c00c905d24..4b2da0866cdc 100644 > --- a/sound/usb/mixer_scarlett_gen2.c > +++ b/sound/usb/mixer_scarlett_gen2.c > @@ -964,8 +964,10 @@ static int scarlett2_add_new_ctl(struct usb_mixer_interface *mixer, > strlcpy(kctl->id.name, name, sizeof(kctl->id.name)); > > err = snd_usb_mixer_add_control(&elem->head, kctl); > - if (err < 0) > + if (err < 0) { > + kfree(elem); > return err; > + } > > if (kctl_return) > *kctl_return = kctl; > -- > 2.17.1 >