From: Michael Pratt <mpratt@google.com>
Date: Mon, 27 Oct 2025 20:17:31 +0000 (-0400)
Subject: internal/runtime/gc/scan: correct size class size check
X-Git-Tag: go1.26rc1~452
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=ff2ebf69c4f099adf90d6c6284f2b3fd2ff789f0;p=gostls13.git

internal/runtime/gc/scan: correct size class size check

This check intends to skip size classes that are too big for scanSpan,
but it compares the size class index with a byte size. It must do the
conversion first.

For #73581.

Change-Id: I6a6a636c8d19fa3bf2a2b609870d67d33f47f66e
Reviewed-on: https://go-review.googlesource.com/c/go/+/715460
Auto-Submit: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
---

diff --git a/src/internal/runtime/gc/scan/scan_test.go b/src/internal/runtime/gc/scan/scan_test.go
index 14a0f6f7f4..1208783b6f 100644
--- a/src/internal/runtime/gc/scan/scan_test.go
+++ b/src/internal/runtime/gc/scan/scan_test.go
@@ -114,7 +114,8 @@ func benchmarkScanSpanPackedAllSizeClasses(b *testing.B, nPages int) {
 		if sc == 0 {
 			continue
 		}
-		if sc >= gc.MinSizeForMallocHeader {
+		size := gc.SizeClassToSize[sc]
+		if size >= gc.MinSizeForMallocHeader {
 			break
 		}
 		b.Run(fmt.Sprintf("sizeclass=%d", sc), func(b *testing.B) {