Don't dereference HostConfig.MemorySwapiness if nil

Signed-off-by: Darren Shepherd <darren@rancher.com>
Upstream-commit: 5ac12c418f163a49ad3355506fc8ed632905dbd9
Component: engine

components/engine/daemon/container_operations_unix.go

@@ -199,7 +199,11 @@ func (daemon *Daemon) populateCommand(c *container.Container, env []string) erro
 		BlkioThrottleReadBpsDevice:  readBpsDevice,
 		BlkioThrottleWriteBpsDevice: writeBpsDevice,
 		OomKillDisable:              c.HostConfig.OomKillDisable,
-		MemorySwappiness:            *c.HostConfig.MemorySwappiness,
+		MemorySwappiness:            -1,
+	}
+
+	if c.HostConfig.MemorySwappiness != nil {
+		resources.MemorySwappiness = *c.HostConfig.MemorySwappiness
 	}
 
 	processConfig := execdriver.ProcessConfig{