fix(tailnet): data race in coordinator.Close() (#4589)

coadler · web-flow · commit 9b5d627a5567 · 2022-10-17T11:47:45.000-05:00
diff --git a/tailnet/coordinator.go b/tailnet/coordinator.go
@@ -338,10 +338,10 @@ func (c *coordinator) handleNextAgentMessage(id uuid.UUID, decoder *json.Decoder
 func (c *coordinator) Close() error {
 	c.mutex.Lock()
 	if c.closed {
+		c.mutex.Unlock()
 		return nil
 	}
 	c.closed = true
-	c.mutex.Unlock()
 
 	wg := sync.WaitGroup{}
 
@@ -365,6 +365,8 @@ func (c *coordinator) Close() error {
 		}
 	}
 
+	c.mutex.Unlock()
+
 	wg.Wait()
 	return nil
 }

Original file line number	Diff line number	Diff line change
`@@ -338,10 +338,10 @@ func (c coordinator) handleNextAgentMessage(id uuid.UUID, decoder json.Decoder`
`338`	`338`	`func (c *coordinator) Close() error {`
`339`	`339`	`c.mutex.Lock()`
`340`	`340`	`if c.closed {`
	`341`	`+ c.mutex.Unlock()`
`341`	`342`	`return nil`
`342`	`343`	`}`
`343`	`344`	`c.closed = true`
`344`		`- c.mutex.Unlock()`
`345`	`345`
`346`	`346`	`wg := sync.WaitGroup{}`
`347`	`347`
`@@ -365,6 +365,8 @@ func (c *coordinator) Close() error {`
`365`	`365`	`}`
`366`	`366`	`}`
`367`	`367`
	`368`	`+ c.mutex.Unlock()`
	`369`	`+`
`368`	`370`	`wg.Wait()`
`369`	`371`	`return nil`
`370`	`372`	`}`