From c1fc209c41c18806b7cef1cf114f1ca9b3731eb9 Mon Sep 17 00:00:00 2001
From: Keith Randall <khr@golang.org>
Date: Wed, 23 Apr 2025 14:15:51 -0700
Subject: [PATCH] runtime: use precise bounds of Go data/bss for race detector
We only want to call into the race detector for Go global variables.
By rounding up the region bounds, we can include some C globals.
Even worse, we can include only *part* of a C global, leading to
race{read,write}range calls which straddle the end of shadow memory.
That causes the race detector to barf.
Fix some off-by-one errors in the assembly comparisons. We want to
skip calling the race detector when addr == racedataend.
Fixes #73483
Change-Id: I436b0f588d6165b61f30cb7653016ba9b7cbf585
Reviewed-on: https://go-review.googlesource.com/c/go/+/667655
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
---
src/runtime/race.go | 10 ++++++----
src/runtime/race_arm64.s | 2 +-
src/runtime/race_ppc64le.s | 2 +-
test/fixedbugs/issue73483.go | 20 ++++++++++++++++++++
4 files changed, 28 insertions(+), 6 deletions(-)
create mode 100644 test/fixedbugs/issue73483.go
diff --git a/src/runtime/race.go b/src/runtime/race.go
index 6b7bbe52458..fa781a3ccc0 100644
--- a/src/runtime/race.go
+++ b/src/runtime/race.go
@@ -455,7 +455,6 @@ func raceinit() (gctx, pctx uintptr) {
racecall(&__tsan_init, uintptr(unsafe.Pointer(&gctx)), uintptr(unsafe.Pointer(&pctx)), abi.FuncPCABI0(racecallbackthunk), 0)
- // Round data segment to page boundaries, because it's used in mmap().
start := ^uintptr(0)
end := uintptr(0)
if start > firstmoduledata.noptrdata {
@@ -482,10 +481,13 @@ func raceinit() (gctx, pctx uintptr) {
if end < firstmoduledata.ebss {
end = firstmoduledata.ebss
}
- size := alignUp(end-start, _PageSize)
- racecall(&__tsan_map_shadow, start, size, 0, 0)
+ // Use exact bounds for boundary check in racecalladdr. See issue 73483.
racedatastart = start
- racedataend = start + size
+ racedataend = end
+ // Round data segment to page boundaries for race detector (TODO: still needed?)
+ start = alignDown(start, _PageSize)
+ end = alignUp(end, _PageSize)
+ racecall(&__tsan_map_shadow, start, end-start, 0, 0)
return
}
diff --git a/src/runtime/race_arm64.s b/src/runtime/race_arm64.s
index c42a6c13775..83dfdef2e50 100644
--- a/src/runtime/race_arm64.s
+++ b/src/runtime/race_arm64.s
@@ -163,7 +163,7 @@ data:
BLT ret
MOVD runtime·racedataend(SB), R10
CMP R10, R1
- BGT ret
+ BGE ret
call:
JMP racecall<>(SB)
ret:
diff --git a/src/runtime/race_ppc64le.s b/src/runtime/race_ppc64le.s
index 43829479bde..d3cac03ff48 100644
--- a/src/runtime/race_ppc64le.s
+++ b/src/runtime/race_ppc64le.s
@@ -153,7 +153,7 @@ data:
BLT ret
MOVD runtime·racedataend(SB), R9
CMP R4, R9
- BGT ret
+ BGE ret
call:
// Careful!! racecall will save LR on its
// stack, which is OK as long as racecalladdr
diff --git a/test/fixedbugs/issue73483.go b/test/fixedbugs/issue73483.go
new file mode 100644
index 00000000000..8cd0c3433a9
--- /dev/null
+++ b/test/fixedbugs/issue73483.go
@@ -0,0 +1,20 @@
+// run -race
+
+//go:build race && cgo
+
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+/*
+ int v[8192];
+*/
+import "C"
+
+var x [8192]C.int
+
+func main() {
+ copy(C.v[:], x[:])
+}
--
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