From d596bc0e819aec2cf65a61d8b92f6bec8e0a7124 Mon Sep 17 00:00:00 2001
From: Damien Neil <dneil@google.com>
Date: Fri, 9 May 2025 16:18:49 -0700
Subject: runtime: disallow closing bubbled chans from outside bubble

A chan created within a synctest bubble may not be
operated on from outside the bubble.
We panicked on send and receive, but not close.
Panic on close as well.

For #67434

Change-Id: I98d39e0cf7baa1a679aca1fb325453d69c535308
Reviewed-on: https://go-review.googlesource.com/c/go/+/671960
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Damien Neil <dneil@google.com>
---
 src/runtime/chan.go | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'src/runtime')

diff --git a/src/runtime/chan.go b/src/runtime/chan.go
index cb2737d096..63d8044b44 100644
--- a/src/runtime/chan.go
+++ b/src/runtime/chan.go
@@ -415,6 +415,9 @@ func closechan(c *hchan) {
 	if c == nil {
 		panic(plainError("close of nil channel"))
 	}
+	if c.synctest && getg().bubble == nil {
+		panic(plainError("close of synctest channel from outside bubble"))
+	}
 
 	lock(&c.lock)
 	if c.closed != 0 {
-- 
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