From: David Goulet <dgoulet@efficios.com>
Date: Thu, 13 Dec 2012 22:51:45 +0000 (-0500)
Subject: Fix: RCU unlock out of error path
X-Git-Tag: v2.1.0~52
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=95e047ff8e01767e2e18b892f7a1ba9bf28abcbe;p=lttng-tools.git

Fix: RCU unlock out of error path

On channel error, RCU was not unlocking the read side. Furthermore,
remove a check for a NULL session that was also not going through an RCU
unlock. Change it to an assert.

This also adds a channel subbuf size check when enabling a channel.

Signed-off-by: David Goulet <dgoulet@efficios.com>
---

diff --git a/src/bin/lttng-sessiond/channel.c b/src/bin/lttng-sessiond/channel.c
index d07e1d901..ae53c672c 100644
--- a/src/bin/lttng-sessiond/channel.c
+++ b/src/bin/lttng-sessiond/channel.c
@@ -240,6 +240,11 @@ int channel_ust_create(struct ltt_ust_session *usess, int domain,
 		attr = defattr;
 	}
 
+	if (attr->attr.subbuf_size < DEFAULT_UST_CHANNEL_SUBBUF_SIZE) {
+		ret = LTTNG_ERR_INVALID;
+		goto error;
+	}
+
 	/*
 	 * Validate UST buffer size and number of buffers: must both be
 	 * power of 2 and nonzero. We validate right here for UST,
diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 384f8e688..607683009 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -2050,7 +2050,7 @@ int ust_app_create_channel_glb(struct ltt_ust_session *usess,
 		if (ua_sess == NULL) {
 			/* The malloc() failed. */
 			ret = -1;
-			goto error;
+			goto error_rcu_unlock;
 		} else if (ua_sess == (void *) -1UL) {
 			/* The application's socket is not valid. Contiuing */
 			ret = -1;
@@ -2062,13 +2062,12 @@ int ust_app_create_channel_glb(struct ltt_ust_session *usess,
 		if (ua_chan == NULL) {
 			/* Major problem here and it's maybe the tracer or malloc() */
 			ret = -1;
-			goto error;
+			goto error_rcu_unlock;
 		}
 	}
 
+error_rcu_unlock:
 	rcu_read_unlock();
-
-error:
 	return ret;
 }
 
@@ -2581,10 +2580,7 @@ void ust_app_global_update(struct ltt_ust_session *usess, int sock)
 	struct ust_app_event *ua_event;
 	struct ust_app_ctx *ua_ctx;
 
-	if (usess == NULL) {
-		ERR("No UST session on global update. Returning");
-		goto error;
-	}
+	assert(usess);
 
 	DBG2("UST app global update for app sock %d for session id %d", sock,
 			usess->id);