From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 13 Jun 2013 21:07:21 +0000 (-0400)
Subject: Fix ua_chan assert
X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=commitdiff_plain;h=4950b860f76b938833046793e7221c11e8e89682

Fix ua_chan assert

delete_ust_app() can remove a channel objd from the hash table
concurrently with notify

Fix #560

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
---

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 396ca936e..ee3b3406d 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -4475,9 +4475,14 @@ static int reply_ust_register_channel(int sock, int sobjd, int cobjd,
 		goto error_rcu_unlock;
 	}
 
-	/* Lookup channel by UST object descriptor. Should always be found. */
+	/* Lookup channel by UST object descriptor. */
 	ua_chan = find_channel_by_objd(app, cobjd);
-	assert(ua_chan);
+	if (!ua_chan) {
+		DBG("Application channel is being teardown. Abort event notify");
+		ret = 0;
+		goto error_rcu_unlock;
+	}
+
 	assert(ua_chan->session);
 	ua_sess = ua_chan->session;
 
@@ -4581,9 +4586,14 @@ static int add_event_ust_registry(int sock, int sobjd, int cobjd, char *name,
 		goto error_rcu_unlock;
 	}
 
-	/* Lookup channel by UST object descriptor. Should always be found. */
+	/* Lookup channel by UST object descriptor. */
 	ua_chan = find_channel_by_objd(app, cobjd);
-	assert(ua_chan);
+	if (!ua_chan) {
+		DBG("Application channel is being teardown. Abort event notify");
+		ret = 0;
+		goto error_rcu_unlock;
+	}
+
 	assert(ua_chan->session);
 	ua_sess = ua_chan->session;