From 2616aadf1c9a130a8db5c95a302283c00561da60 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 24 Apr 2018 07:26:59 +0200 Subject: [PATCH] ALSA: seq: oss: Fix unbalanced use lock for synth MIDI device 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(-) diff --git a/sound/core/seq/oss/seq_oss_synth.c b/sound/core/seq/oss/seq_oss_synth.c index ac3d7d2125e99..760b340921103 100644 --- 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, int dev) 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; -- 2.47.3