From: Michael Anthony Knyszek <mknyszek@google.com>
Date: Tue, 12 Aug 2025 21:57:23 +0000 (+0000)
Subject: internal/runtime/gc/scan: avoid -1 index when cache sizes unavailable
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=adbf59525c06ae7e037ad0e9a7709ebed2528d66;p=gostls13.git

internal/runtime/gc/scan: avoid -1 index when cache sizes unavailable

Fixes #74984.
Fixes #74983.

Change-Id: I011c66c2005bc4d92f1d17f1f8ce88158634f71f
Reviewed-on: https://go-review.googlesource.com/c/go/+/695476
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---

diff --git a/src/internal/runtime/gc/scan/scan_test.go b/src/internal/runtime/gc/scan/scan_test.go
index 9b577155ed..14a0f6f7f4 100644
--- a/src/internal/runtime/gc/scan/scan_test.go
+++ b/src/internal/runtime/gc/scan/scan_test.go
@@ -100,6 +100,9 @@ func benchmarkCacheSizes(b *testing.B, fn func(b *testing.B, heapPages int)) {
 			fn(b, pages)
 		})
 	}
+	if len(cacheSizes) == 0 {
+		return
+	}
 	ramPages := int(cacheSizes[len(cacheSizes)-1]*3/2) / gc.PageSize
 	b.Run(fmt.Sprintf("cache=ram/pages=%d", ramPages), func(b *testing.B) {
 		fn(b, ramPages)