diff --git a/src/runtime/rand.go b/src/runtime/rand.go
index 6cb8deef51..10cd116fad 100644
--- a/src/runtime/rand.go
+++ b/src/runtime/rand.go
@@ -223,3 +223,25 @@ func cheaprandn(n uint32) uint32 {
 	// See https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/
 	return uint32((uint64(cheaprand()) * uint64(n)) >> 32)
 }
+
+// Too much legacy code has go:linkname references
+// to runtime.fastrand and friends, so keep these around for now.
+// Code should migrate to math/rand/v2.Uint64,
+// which is just as fast, but that's only available in Go 1.22+.
+// It would be reasonable to remove these in Go 1.24.
+// Do not call these from package runtime.
+
+//go:linkname legacy_fastrand runtime.fastrand
+func legacy_fastrand() uint32 {
+	return uint32(rand())
+}
+
+//go:linkname legacy_fastrandn runtime.fastrandn
+func legacy_fastrandn(n uint32) uint32 {
+	return randn(n)
+}
+
+//go:linkname legacy_fastrand64 runtime.fastrand64
+func legacy_fastrand64() uint64 {
+	return rand()
+}
diff --git a/src/runtime/rand_test.go b/src/runtime/rand_test.go
index 94648c5216..baecb6984d 100644
--- a/src/runtime/rand_test.go
+++ b/src/runtime/rand_test.go
@@ -8,6 +8,7 @@ import (
 	. "runtime"
 	"strconv"
 	"testing"
+	_ "unsafe" // for go:linkname
 )
 
 func TestReadRandom(t *testing.T) {
@@ -62,3 +63,35 @@ func BenchmarkFastrandn(b *testing.B) {
 		})
 	}
 }
+
+//go:linkname fastrand runtime.fastrand
+func fastrand() uint32
+
+//go:linkname fastrandn runtime.fastrandn
+func fastrandn(uint32) uint32
+
+//go:linkname fastrand64 runtime.fastrand64
+func fastrand64() uint64
+
+func TestLegacyFastrand(t *testing.T) {
+	// Testing mainly that the calls work at all,
+	// but check that all three don't return the same number (1 in 2^64 chance)
+	{
+		x, y, z := fastrand(), fastrand(), fastrand()
+		if x == y && y == z {
+			t.Fatalf("fastrand three times = %#x, %#x, %#x, want different numbers", x, y, z)
+		}
+	}
+	{
+		x, y, z := fastrandn(1e9), fastrandn(1e9), fastrandn(1e9)
+		if x == y && y == z {
+			t.Fatalf("fastrandn three times = %#x, %#x, %#x, want different numbers", x, y, z)
+		}
+	}
+	{
+		x, y, z := fastrand64(), fastrand64(), fastrand64()
+		if x == y && y == z {
+			t.Fatalf("fastrand64 three times = %#x, %#x, %#x, want different numbers", x, y, z)
+		}
+	}
+}