Merged changes from trunk 1699:1751 into 2.1-staging

git-svn-id: svn://localhost/ardour2/branches/2.1-staging@1752 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 10 insertions, 1 deletions

diff --git a/libs/ardour/audio_diskstream.cc b/libs/ardour/audio_diskstream.cc
index 48085d4922..b372c14b57 100644
--- a/libs/ardour/audio_diskstream.cc
+++ b/libs/ardour/audio_diskstream.cc
@@ -610,7 +610,16 @@ AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_
 
 	if (nominally_recording || rec_nframes) {
 
-		for (n = 0, chan = c->begin(); chan != c->end(); ++chan, ++n) {
+		uint32_t limit = _io->n_inputs ();
+
+		/* one or more ports could already have been removed from _io, but our
+		   channel setup hasn't yet been updated. prevent us from trying to
+		   use channels that correspond to missing ports. note that the
+		   process callback (from which this is called) is always atomic
+		   with respect to port removal/addition.
+		*/
+
+		for (n = 0, chan = c->begin(); chan != c->end() && n < limit; ++chan, ++n) {
 			
 			ChannelInfo* chaninfo (*chan);