diff --git a/ChangeLog b/ChangeLog
index 657c41b76a..5c32c2fb44 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2008-05-06  Sebastian Dröge  <slomo@circular-chaos.org>
+
+	* gst/volume/gstvolume.c: (volume_transform_ip):
+	Return NOT_NEGOTIATED if we didn't set a process function yet for some
+	reason instead of crashing later. Might fix bug #509125.
+
 2008-05-06  Sebastian Dröge  <slomo@circular-chaos.org>
 
 	Based on a patch by: Tim-Philipp Müller  <tim.muller at collabora co uk>
diff --git a/gst/volume/gstvolume.c b/gst/volume/gstvolume.c
index b5bceb4a5a..c167f0fbdd 100644
--- a/gst/volume/gstvolume.c
+++ b/gst/volume/gstvolume.c
@@ -689,6 +689,8 @@ volume_transform_ip (GstBaseTransform * base, GstBuffer * outbuf)
   GstVolume *this = GST_VOLUME (base);
   GstClockTime timestamp;
 
+  g_return_val_if_fail (this->process != NULL, GST_FLOW_NOT_NEGOTIATED);
+
   /* FIXME: if controllers are bound, subdivide GST_BUFFER_SIZE into small
    * chunks for smooth fades, what is small? 1/10th sec.
    */