ALSA: seq: oss: Fix unbalanced use lock for synth MIDI device

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: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2018-04-24 07:26:59 +02:00
parent ab3b8e5159
commit f5e94b4c6e

View File

@ -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;