From: Andre Noll <maan@systemlinux.org>
Date: Thu, 30 Jan 2014 21:49:45 +0000 (+0100)
Subject: ao_write: Fix spurious segfault.
X-Git-Tag: v0.5.3~20^2~8
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=751e3811e99c744f9f651b191950010ce118eb78

ao_write: Fix spurious segfault.

Both btr_node_status() and btr_consume() access the buffer tree of
the ao writer, so these functions must be called with the pthread
mutex locked.
---

diff --git a/ao_write.c b/ao_write.c
index 730653c1..52c4b11e 100644
--- a/ao_write.c
+++ b/ao_write.c
@@ -48,7 +48,14 @@ static void aow_close(struct writer_node *wn)
 static void aow_pre_select(struct sched *s, struct task *t)
 {
 	struct writer_node *wn = container_of(t, struct writer_node, task);
-	int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
+	struct private_aow_data *pawd = wn->private_data;
+	int ret;
+
+	if (pawd)
+		pthread_mutex_lock(&pawd->mutex);
+	ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
+	if (pawd)
+		pthread_mutex_unlock(&pawd->mutex);
 
 	if (ret == 0)
 		return;
@@ -223,7 +230,9 @@ __noreturn static void *aow_play(void *priv)
 		ret = -E_AO_PLAY;
 		if (ao_play(pawd->dev, data, bytes) == 0) /* failure */
 			goto out;
+		pthread_mutex_lock(&pawd->mutex);
 		btr_consume(btrn, bytes);
+		pthread_mutex_unlock(&pawd->mutex);
 	}
 unlock:
 	pthread_mutex_unlock(&pawd->mutex);