[PATCH 2/2] ALSA: seq: Avoid client data changes during proc reads

[Takashi Iwai <tiwai@suse.de>]

The proc read of each client should protect against the concurrent
data changes to keep the data consistent; although they are supposed
to be safe and won't crash things, it doesn't guarantee the
consistency between the read values.  Take client->ioctl_mutex for
protecting against the concurrent changes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/core/seq/seq_clientmgr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c
index 659494e00c51..fe7cd0649c98 100644
--- a/sound/core/seq/seq_clientmgr.c
+++ b/sound/core/seq/seq_clientmgr.c
@@ -2706,6 +2706,7 @@ void snd_seq_info_clients_read(struct snd_info_entry *entry,
 			continue;
 		}
 
+		mutex_lock(&client->ioctl_mutex);
 		snd_iprintf(buffer, "Client %3d : \"%s\" [%s %s]\n",
 			    c, client->name,
 			    client->type == USER_CLIENT ? "User" : "Kernel",
@@ -2723,6 +2724,7 @@ void snd_seq_info_clients_read(struct snd_info_entry *entry,
 			snd_iprintf(buffer, "  Input pool :\n");
 			snd_seq_info_pool(buffer, client->data.user.fifo->pool, "    ");
 		}
+		mutex_unlock(&client->ioctl_mutex);
 		snd_seq_client_unlock(client);
 	}
 }
-- 
2.43.0