From f259e7352aa1992dd800221db60be4866a2449e6 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Fri, 29 May 2015 11:30:56 -0700
Subject: [PATCH] packer/plugin: fix crash case, nil function call [GH-2098]

---
 CHANGELOG.md                    | 1 +
 packer/plugin/post_processor.go | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d9480f72..42f2e4f3e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ IMPROVEMENTS:
 
 BUG FIXES:
 
+  * core: Fix potential panic for post-processor plugin exits [GH-2098]
   * builder/amazon: Remove deprecated ec2-upload-bundle paramger [GH-1931]
   * builder/amazon: Retry finding created instance for eventual
       consistency. [GH-2129]
diff --git a/packer/plugin/post_processor.go b/packer/plugin/post_processor.go
index 72398020f..483140564 100644
--- a/packer/plugin/post_processor.go
+++ b/packer/plugin/post_processor.go
@@ -29,7 +29,7 @@ func (c *cmdPostProcessor) PostProcess(ui packer.Ui, a packer.Artifact) (packer.
 }
 
 func (c *cmdPostProcessor) checkExit(p interface{}, cb func()) {
-	if c.client.Exited() {
+	if c.client.Exited() && cb != nil {
 		cb()
 	} else if p != nil && !Killed {
 		log.Panic(p)