patch 7.4.1507
Problem:    Crash when starting a job fails.
Solution:   Check for the channel to be NULL.  (idea by Yasuhiro Matsumoto)
diff --git a/src/eval.c b/src/eval.c
index 77638d5..f65c9a0 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -15262,7 +15262,8 @@
 
 #ifdef FEAT_CHANNEL
     /* If the channel is reading from a buffer, write lines now. */
-    channel_write_in(job->jv_channel);
+    if (job->jv_channel != NULL)
+	channel_write_in(job->jv_channel);
 #endif
 
 theend: