[ALSA] Fix races in PCM OSS emulation

Fixed the race among multiple threads accessing the OSS PCM
instance concurrently by simply introducing a mutex for protecting
a setup of the PCM.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/sound/pcm_oss.h b/include/sound/pcm_oss.h
index c854647b6f3c..1cd4f64cdf31 100644
--- a/include/sound/pcm_oss.h
+++ b/include/sound/pcm_oss.h
@@ -56,6 +56,7 @@ struct snd_pcm_oss_runtime {
         size_t mmap_bytes;
         char *buffer;                           /* vmallocated period */
         size_t buffer_used;                     /* used length from period buffer */
+        struct mutex params_lock;
 #ifdef CONFIG_SND_PCM_OSS_PLUGINS
         struct snd_pcm_plugin *plugin_first;
         struct snd_pcm_plugin *plugin_last;