From aa2dd8491ca2107ca525bfe21af01da3ee301898 Mon Sep 17 00:00:00 2001
From: Thulinma <jaron@vietors.com>
Date: Sun, 1 May 2016 15:56:10 +0200
Subject: [PATCH] Fixed a segfault in the buffer on track deletion, added a
 WARN-level message when/if something similar occurs.

---
 lib/shared_memory.cpp      |  3 +++
 src/input/input_buffer.cpp | 20 ++++++++++++--------
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/lib/shared_memory.cpp b/lib/shared_memory.cpp
index 49a3a4b1..9af28ed8 100644
--- a/lib/shared_memory.cpp
+++ b/lib/shared_memory.cpp
@@ -1116,6 +1116,9 @@ namespace IPC {
 
   userConnection::userConnection(char * _data) {
     data = _data;
+    if (!data){
+      WARN_MSG("userConnection created with null pointer!");
+    }
   }
 
   unsigned long userConnection::getTrackId(size_t offset) const {
diff --git a/src/input/input_buffer.cpp b/src/input/input_buffer.cpp
index dea4efc1..444bce24 100644
--- a/src/input/input_buffer.cpp
+++ b/src/input/input_buffer.cpp
@@ -514,14 +514,18 @@ namespace Mist {
             nProxy.curPage.erase(tid);
             bufferLocations[tid].erase(bufferLocations[tid].begin());
           }
-          if (pushLocation.count(it->first)){
-            //Reset the userpage, to allow repushing from TS
-            IPC::userConnection userConn(pushLocation[it->first]);
-            for (int i = 0; i < SIMUL_TRACKS; i++){
-              if (userConn.getTrackId(i) == it->first) {
-                userConn.setTrackId(i, 0);
-                userConn.setKeynum(i, 0);
-                break;
+          if (pushLocation.count(it->first)) {
+            // \todo Debugger says this is null sometimes. It shouldn't be. Figure out why!
+            // For now, this if will prevent crashes in these cases.
+            if (pushLocation[it->first]){
+              //Reset the userpage, to allow repushing from TS
+              IPC::userConnection userConn(pushLocation[it->first]);
+              for (int i = 0; i < SIMUL_TRACKS; i++) {
+                if (userConn.getTrackId(i) == it->first) {
+                  userConn.setTrackId(i, 0);
+                  userConn.setKeynum(i, 0);
+                  break;
+                }
               }
             }
             pushLocation.erase(it->first);