From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:57404 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755085AbeD3TXz (ORCPT ); Mon, 30 Apr 2018 15:23:55 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai Subject: [PATCH 3.18 17/25] ALSA: seq: oss: Fix unbalanced use lock for synth MIDI device Date: Mon, 30 Apr 2018 12:23:24 -0700 Message-Id: <20180430183911.517053143@linuxfoundation.org> In-Reply-To: <20180430183910.801976983@linuxfoundation.org> References: <20180430183910.801976983@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit f5e94b4c6ebdabe0f602d796e0430180927521a0 upstream. When get_synthdev() is called for a MIDI device, it returns the fixed midi_synth_dev without the use refcounting. OTOH, the caller is supposed to unreference unconditionally after the usage, so this would lead to unbalanced refcount. This patch corrects the behavior and keep up the refcount balance also for the MIDI synth device. Cc: Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/seq/oss/seq_oss_synth.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/sound/core/seq/oss/seq_oss_synth.c +++ b/sound/core/seq/oss/seq_oss_synth.c @@ -363,10 +363,14 @@ get_synthdev(struct seq_oss_devinfo *dp, return NULL; if (! dp->synths[dev].opened) return NULL; - if (dp->synths[dev].is_midi) - return &midi_synth_dev; - if ((rec = get_sdev(dev)) == NULL) - return NULL; + if (dp->synths[dev].is_midi) { + rec = &midi_synth_dev; + snd_use_lock_use(&rec->use_lock); + } else { + rec = get_sdev(dev); + if (!rec) + return NULL; + } if (! rec->opened) { snd_use_lock_free(&rec->use_lock); return NULL;