tun: fix race during WriteNotify and Close

spikecurtis · spikecurtis · commit a4cb23ac736d · 2024-05-02T16:27:27.000+04:00
Signed-off-by: Spike Curtis &lt;spike@coder.com&gt;
diff --git a/tun/netstack/tun.go b/tun/netstack/tun.go
@@ -166,7 +166,7 @@ func (tun *netTun) WriteNotify() {
 }
 
 func (tun *netTun) Close() error {
-	tun.stack.RemoveNIC(1)
+	tun.stack.Destroy()
 
 	if tun.events != nil {
 		close(tun.events)
@@ -175,6 +175,8 @@ func (tun *netTun) Close() error {
 	tun.ep.Close()
 
 	if tun.incomingPacket != nil {
+		// It's safe to close the channel here because tun.stack.Destroy() ensures that no worker
+		// goroutines could be calling WriteNotify()
 		close(tun.incomingPacket)
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -166,7 +166,7 @@ func (tun *netTun) WriteNotify() {`
`166`	`166`	`}`
`167`	`167`
`168`	`168`	`func (tun *netTun) Close() error {`
`169`		`- tun.stack.RemoveNIC(1)`
	`169`	`+ tun.stack.Destroy()`
`170`	`170`
`171`	`171`	`if tun.events != nil {`
`172`	`172`	`close(tun.events)`
`@@ -175,6 +175,8 @@ func (tun *netTun) Close() error {`
`175`	`175`	`tun.ep.Close()`
`176`	`176`
`177`	`177`	`if tun.incomingPacket != nil {`
	`178`	`+ // It's safe to close the channel here because tun.stack.Destroy() ensures that no worker`
	`179`	`+ // goroutines could be calling WriteNotify()`
`178`	`180`	`close(tun.incomingPacket)`
`179`	`181`	`}`
`180`	`182`