Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965785AbeAOMkl (ORCPT + 1 other); Mon, 15 Jan 2018 07:40:41 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:46704 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965753AbeAOMkh (ORCPT ); Mon, 15 Jan 2018 07:40:37 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai Subject: [PATCH 4.4 21/87] ALSA: aloop: Release cable upon open error path Date: Mon, 15 Jan 2018 13:34:20 +0100 Message-Id: <20180115123351.453457264@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180115123349.252309699@linuxfoundation.org> References: <20180115123349.252309699@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 9685347aa0a5c2869058ca6ab79fd8e93084a67f upstream. The aloop runtime object and its assignment in the cable are left even when opening a substream fails. This doesn't mean any memory leak, but it still keeps the invalid pointer that may be referred by the another side of the cable spontaneously, which is a potential Oops cause. Clean up the cable assignment and the empty cable upon the error path properly. Fixes: 597603d615d2 ("ALSA: introduce the snd-aloop module for the PCM loopback") Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/drivers/aloop.c | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-) --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -658,12 +658,31 @@ static int rule_channels(struct snd_pcm_ return snd_interval_refine(hw_param_interval(params, rule->var), &t); } +static void free_cable(struct snd_pcm_substream *substream) +{ + struct loopback *loopback = substream->private_data; + int dev = get_cable_index(substream); + struct loopback_cable *cable; + + cable = loopback->cables[substream->number][dev]; + if (!cable) + return; + if (cable->streams[!substream->stream]) { + /* other stream is still alive */ + cable->streams[substream->stream] = NULL; + } else { + /* free the cable */ + loopback->cables[substream->number][dev] = NULL; + kfree(cable); + } +} + static int loopback_open(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; struct loopback *loopback = substream->private_data; struct loopback_pcm *dpcm; - struct loopback_cable *cable; + struct loopback_cable *cable = NULL; int err = 0; int dev = get_cable_index(substream); @@ -682,7 +701,6 @@ static int loopback_open(struct snd_pcm_ if (!cable) { cable = kzalloc(sizeof(*cable), GFP_KERNEL); if (!cable) { - kfree(dpcm); err = -ENOMEM; goto unlock; } @@ -724,6 +742,10 @@ static int loopback_open(struct snd_pcm_ else runtime->hw = cable->hw; unlock: + if (err < 0) { + free_cable(substream); + kfree(dpcm); + } mutex_unlock(&loopback->cable_lock); return err; } @@ -732,20 +754,10 @@ static int loopback_close(struct snd_pcm { struct loopback *loopback = substream->private_data; struct loopback_pcm *dpcm = substream->runtime->private_data; - struct loopback_cable *cable; - int dev = get_cable_index(substream); loopback_timer_stop(dpcm); mutex_lock(&loopback->cable_lock); - cable = loopback->cables[substream->number][dev]; - if (cable->streams[!substream->stream]) { - /* other stream is still alive */ - cable->streams[substream->stream] = NULL; - } else { - /* free the cable */ - loopback->cables[substream->number][dev] = NULL; - kfree(cable); - } + free_cable(substream); mutex_unlock(&loopback->cable_lock); return 0; }