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=-6.8 required=3.0 tests=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 6A32FCA9EC0 for ; Mon, 28 Oct 2019 16:38:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 459BD214E0 for ; Mon, 28 Oct 2019 16:38:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403802AbfJ1Qik (ORCPT ); Mon, 28 Oct 2019 12:38:40 -0400 Received: from mx2.suse.de ([195.135.220.15]:44082 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1733084AbfJ1Qik (ORCPT ); Mon, 28 Oct 2019 12:38:40 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 2E8A7B2FE; Mon, 28 Oct 2019 16:38:38 +0000 (UTC) Date: Mon, 28 Oct 2019 17:38:37 +0100 Message-ID: From: Takashi Iwai To: Navid Emamdoost Cc: Navid Emamdoost , Kangjie Lu , Stephen McCamant , Clemens Ladisch , Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, LKML Subject: Re: [PATCH] ALSA: usb-audio: Fix memory leak in __snd_usbmidi_create In-Reply-To: References: <20191027221007.14317-1-navid.emamdoost@gmail.com> 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 Mon, 28 Oct 2019 17:25:41 +0100, Navid Emamdoost wrote: > > Thanks for the explanation, > > On Mon, Oct 28, 2019 at 1:27 AM Takashi Iwai wrote: > > > > On Sun, 27 Oct 2019 23:10:06 +0100, > > Navid Emamdoost wrote: > > > > > > In the implementation of __snd_usbmidi_create() there is a memory leak > > > caused by incorrect goto destination. Go to free_midi if > > > snd_usbmidi_create_endpoints_midiman() or snd_usbmidi_create_endpoints() > > > fail. > > > > No, this will lead to double-free. After registering the rawmidi > > interface at snd_usbmidi_create_rawmidi(), the common destructor will > > be called via rawmidi private_free callback, and this will release the > > all resources already. > Now I can see how rawmidi private_free is set up to release the > resources, but what concerns me is that at the moment of endpoint/port > creation umidi is not yet added to the midi_list. > In other words, what I see is that we still have just one local > pointer to umidi if any of snd_usbmidi_create_endpoint* fail. > Am I missing something? The rawmidi object that is created via snd_rawmidi_new() is managed via snd_device list, and it's traversed at snd_card_disconnect() and snd_card_free() calls. It's something like devm-stuff (but implemented in a different way). The midi_list is an explicit list for the USB MIDI driver, and it's an individual one from the device list. Takashi > > > > > > > > thanks, > > > > Takashi > > > > > > > > Fixes: 731209cc0417 ("ALSA: usb-midi: Use common error handling code in __snd_usbmidi_create()") > > > Signed-off-by: Navid Emamdoost > > > --- > > > sound/usb/midi.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/sound/usb/midi.c b/sound/usb/midi.c > > > index b737f0ec77d0..22db37fbfbbd 100644 > > > --- a/sound/usb/midi.c > > > +++ b/sound/usb/midi.c > > > @@ -2476,7 +2476,7 @@ int __snd_usbmidi_create(struct snd_card *card, > > > else > > > err = snd_usbmidi_create_endpoints(umidi, endpoints); > > > if (err < 0) > > > - goto exit; > > > + goto free_midi; > > > > > > usb_autopm_get_interface_no_resume(umidi->iface); > > > > > > -- > > > 2.17.1 > > > > > > > -- > Navid. >