From: Nicolas Hillegeer <aktau@google.com>
Date: Thu, 12 Dec 2024 16:35:17 +0000 (-0800)
Subject: runtime: only read pp.m in schedtrace if needed
X-Git-Tag: go1.25rc1~1002
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=ecda82012d3cff21c758fa45eb5e86365015a131;p=gostls13.git

runtime: only read pp.m in schedtrace if needed

Change-Id: Iad3353431a2ef97c1e0c440bdd84b78cb5ea990e
Reviewed-on: https://go-review.googlesource.com/c/go/+/635635
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Nicolas Hillegeer <aktau@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---

diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index ce6cf88d0c..c9d04edd07 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -6391,11 +6391,11 @@ func schedtrace(detailed bool) {
 	// Even if we hold schedlock, most data can be changed concurrently.
 	// E.g. (p->m ? p->m->id : -1) can crash if p->m changes from non-nil to nil.
 	for i, pp := range allp {
-		mp := pp.m.ptr()
 		h := atomic.Load(&pp.runqhead)
 		t := atomic.Load(&pp.runqtail)
 		if detailed {
 			print("  P", i, ": status=", pp.status, " schedtick=", pp.schedtick, " syscalltick=", pp.syscalltick, " m=")
+			mp := pp.m.ptr()
 			if mp != nil {
 				print(mp.id)
 			} else {