From 0b12e3d81cdba8a5676d6d61970d3dc5cb1462ac Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek <mknyszek@google.com>
Date: Thu, 1 Feb 2024 04:47:22 +0000
Subject: [PATCH] runtime: model wakeableSleep.lock in the race detector

Currently the flight recorder tests are failing in race mode because the
race detector doesn't see s.lock, leading to false positives. This has
also appeared in the trace tests. Model the lock in the race detector.

Fixes #65207.
Fixes #65283.

Change-Id: I1e9a5c9606536f55fdfc46b5f8443e9c7213c23d
Reviewed-on: https://go-review.googlesource.com/c/go/+/560215
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
---
 src/runtime/trace2.go | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/runtime/trace2.go b/src/runtime/trace2.go
index 3639adaa1571da..d40596f39be985 100644
--- a/src/runtime/trace2.go
+++ b/src/runtime/trace2.go
@@ -932,7 +932,13 @@ func newWakeableSleep() *wakeableSleep {
 func (s *wakeableSleep) sleep(ns int64) {
 	resetTimer(s.timer, nanotime()+ns)
 	lock(&s.lock)
+	if raceenabled {
+		raceacquire(unsafe.Pointer(&s.lock))
+	}
 	wakeup := s.wakeup
+	if raceenabled {
+		racerelease(unsafe.Pointer(&s.lock))
+	}
 	unlock(&s.lock)
 	<-wakeup
 	stopTimer(s.timer)
@@ -945,6 +951,9 @@ func (s *wakeableSleep) wake() {
 	// Grab the wakeup channel, which may be nil if we're
 	// racing with close.
 	lock(&s.lock)
+	if raceenabled {
+		raceacquire(unsafe.Pointer(&s.lock))
+	}
 	if s.wakeup != nil {
 		// Non-blocking send.
 		//
@@ -956,6 +965,9 @@ func (s *wakeableSleep) wake() {
 		default:
 		}
 	}
+	if raceenabled {
+		racerelease(unsafe.Pointer(&s.lock))
+	}
 	unlock(&s.lock)
 }
 
@@ -969,11 +981,18 @@ func (s *wakeableSleep) wake() {
 func (s *wakeableSleep) close() {
 	// Set wakeup to nil so that a late timer ends up being a no-op.
 	lock(&s.lock)
+	if raceenabled {
+		raceacquire(unsafe.Pointer(&s.lock))
+	}
 	wakeup := s.wakeup
 	s.wakeup = nil
 
 	// Close the channel.
 	close(wakeup)
+
+	if raceenabled {
+		racerelease(unsafe.Pointer(&s.lock))
+	}
 	unlock(&s.lock)
 	return
 }