From: Leonard Wang <wangdeyu0907@gmail.com>
Date: Sun, 24 Apr 2022 04:14:13 +0000 (+0800)
Subject: runtime: set userForced while holding gcsema
X-Git-Tag: go1.20rc1~1068
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=6f7c9ea855b1ae97871837abf33b85aaa6731eae;p=gostls13.git

runtime: set userForced while holding gcsema

Fixes #52515

Change-Id: If10068a97733daf61aba72da5ed3935db8eed8b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/401776
Reviewed-by: hopehook <hopehook@golangcn.org>
Run-TryBot: hopehook <hopehook@golangcn.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Jenny Rakoczy <jenny@golang.org>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Jenny Rakoczy <jenny@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
---

diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index 3243a15b4d..f7e54d3dd3 100644
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -612,9 +612,6 @@ func gcStart(trigger gcTrigger) {
 		return
 	}
 
-	// For stats, check if this GC was forced by the user.
-	work.userForced = trigger.kind == gcTriggerCycle
-
 	// In gcstoptheworld debug mode, upgrade the mode accordingly.
 	// We do this after re-checking the transition condition so
 	// that multiple goroutines that detect the heap trigger don't
@@ -630,6 +627,10 @@ func gcStart(trigger gcTrigger) {
 	semacquire(&gcsema)
 	semacquire(&worldsema)
 
+	// For stats, check if this GC was forced by the user.
+	// Update it under gcsema to avoid gctrace getting wrong values.
+	work.userForced = trigger.kind == gcTriggerCycle
+
 	if trace.enabled {
 		traceGCStart()
 	}