From a95454b6f31a982f064d262987199fba19f085e9 Mon Sep 17 00:00:00 2001
From: Meng Zhuo <mzh@golangcn.org>
Date: Mon, 29 Mar 2021 15:10:50 +0800
Subject: [PATCH] runtime: init plan9 hashkey by time

Maphash requires non-zero integer for initial hashkey

Fixes #45090

Change-Id: Ie567f648c19e81cddc8e72a1c64809fbf52df188
Reviewed-on: https://go-review.googlesource.com/c/go/+/303969
Trust: Meng Zhuo <mzh@golangcn.org>
Run-TryBot: Meng Zhuo <mzh@golangcn.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Richard Miller <millerresearch@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
---
 src/runtime/os_plan9.go | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/runtime/os_plan9.go b/src/runtime/os_plan9.go
index 77665f461a..4d428346f0 100644
--- a/src/runtime/os_plan9.go
+++ b/src/runtime/os_plan9.go
@@ -325,7 +325,23 @@ func crash() {
 
 //go:nosplit
 func getRandomData(r []byte) {
-	extendRandom(r, 0)
+	// inspired by wyrand see hash32.go for detail
+	t := nanotime()
+	v := getg().m.procid ^ uint64(t)
+
+	for len(r) > 0 {
+		v ^= 0xa0761d6478bd642f
+		v *= 0xe7037ed1a0b428db
+		size := 8
+		if len(r) < 8 {
+			size = len(r)
+		}
+		for i := 0; i < size; i++ {
+			r[i] = byte(v >> (8 * i))
+		}
+		r = r[size:]
+		v = v>>32 | v<<32
+	}
 }
 
 func initsig(preinit bool) {