Ok, second take on fixing the handling of comm.-

Process.c

@@ -140,6 +140,7 @@ Process* Process_new(struct ProcessList_ *pl) {
 Process* Process_clone(Process* this) {
    Process* clone = malloc(sizeof(Process));
    memcpy(clone, this, sizeof(Process));
+   this->comm = NULL;
    return clone;
 }
 

ProcessList.c

@@ -526,10 +526,7 @@ void ProcessList_processEntries(ProcessList* this, char* dirname, int parent, fl
             assert(process->pid == pid);
          } else {
             process = prototype;
-            if (process->comm) {
-               free(process->comm);
-               process->comm = NULL;
-            }
+            assert(process->comm == NULL);
             process->pid = pid;
             if (! ProcessList_readStatusFile(this, process, dirname, name))
                goto errorReadingProcess;
@@ -611,6 +608,10 @@ void ProcessList_processEntries(ProcessList* this, char* dirname, int parent, fl
          errorReadingProcess: {
             if (existingProcess)
                ProcessList_remove(this, process);
+            if (process->comm) {
+               free(process->comm);
+               process->comm = NULL;
+            }
          }
       }
    }