From e126f30a662ea6bd622d69c9fd85499b612fb6b3 Mon Sep 17 00:00:00 2001
From: Austin Clements <austin@google.com>
Date: Tue, 17 Nov 2015 17:20:38 -0500
Subject: [PATCH] runtime: recursively disallow write barriers in sighandler

sighandler may run during STW, so write barriers are not allowed.

Change-Id: Icdf46be10ea296fd87e73ab56ebb718c5d3c97ac
Reviewed-on: https://go-review.googlesource.com/17007
Reviewed-by: Russ Cox <rsc@golang.org>
---
 src/runtime/os3_plan9.go      | 3 ++-
 src/runtime/signal_386.go     | 3 ++-
 src/runtime/signal_amd64x.go  | 3 ++-
 src/runtime/signal_arm.go     | 3 ++-
 src/runtime/signal_arm64.go   | 3 ++-
 src/runtime/signal_mips64x.go | 3 ++-
 src/runtime/signal_ppc64x.go  | 3 ++-
 7 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/runtime/os3_plan9.go b/src/runtime/os3_plan9.go
index f660cc72a7..edd66c59b3 100644
--- a/src/runtime/os3_plan9.go
+++ b/src/runtime/os3_plan9.go
@@ -10,7 +10,8 @@ import (
 )
 
 // May run during STW, so write barriers are not allowed.
-//go:nowritebarrier
+//
+//go:nowritebarrierrec
 func sighandler(_ureg *ureg, note *byte, gp *g) int {
 	_g_ := getg()
 	var t sigTabT
diff --git a/src/runtime/signal_386.go b/src/runtime/signal_386.go
index 90d69ee389..3ea0656e65 100644
--- a/src/runtime/signal_386.go
+++ b/src/runtime/signal_386.go
@@ -30,7 +30,8 @@ func dumpregs(c *sigctxt) {
 var crashing int32
 
 // May run during STW, so write barriers are not allowed.
-//go:nowritebarrier
+//
+//go:nowritebarrierrec
 func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
 	_g_ := getg()
 	c := &sigctxt{info, ctxt}
diff --git a/src/runtime/signal_amd64x.go b/src/runtime/signal_amd64x.go
index df317e3835..ad3187337a 100644
--- a/src/runtime/signal_amd64x.go
+++ b/src/runtime/signal_amd64x.go
@@ -39,7 +39,8 @@ func dumpregs(c *sigctxt) {
 var crashing int32
 
 // May run during STW, so write barriers are not allowed.
-//go:nowritebarrier
+//
+//go:nowritebarrierrec
 func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
 	_g_ := getg()
 	c := &sigctxt{info, ctxt}
diff --git a/src/runtime/signal_arm.go b/src/runtime/signal_arm.go
index c00e43d0c2..e8d19a454d 100644
--- a/src/runtime/signal_arm.go
+++ b/src/runtime/signal_arm.go
@@ -35,7 +35,8 @@ func dumpregs(c *sigctxt) {
 var crashing int32
 
 // May run during STW, so write barriers are not allowed.
-//go:nowritebarrier
+//
+//go:nowritebarrierrec
 func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
 	_g_ := getg()
 	c := &sigctxt{info, ctxt}
diff --git a/src/runtime/signal_arm64.go b/src/runtime/signal_arm64.go
index 96a4cb3dac..2966ec0b20 100644
--- a/src/runtime/signal_arm64.go
+++ b/src/runtime/signal_arm64.go
@@ -51,7 +51,8 @@ func dumpregs(c *sigctxt) {
 var crashing int32
 
 // May run during STW, so write barriers are not allowed.
-//go:nowritebarrier
+//
+//go:nowritebarrierrec
 func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
 	_g_ := getg()
 	c := &sigctxt{info, ctxt}
diff --git a/src/runtime/signal_mips64x.go b/src/runtime/signal_mips64x.go
index 51598e8e5a..f30ff6e9e9 100644
--- a/src/runtime/signal_mips64x.go
+++ b/src/runtime/signal_mips64x.go
@@ -54,7 +54,8 @@ func dumpregs(c *sigctxt) {
 var crashing int32
 
 // May run during STW, so write barriers are not allowed.
-//go:nowritebarrier
+//
+//go:nowritebarrierrec
 func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
 	_g_ := getg()
 	c := &sigctxt{info, ctxt}
diff --git a/src/runtime/signal_ppc64x.go b/src/runtime/signal_ppc64x.go
index 774aa42c77..e0c5f91e33 100644
--- a/src/runtime/signal_ppc64x.go
+++ b/src/runtime/signal_ppc64x.go
@@ -56,7 +56,8 @@ func dumpregs(c *sigctxt) {
 var crashing int32
 
 // May run during STW, so write barriers are not allowed.
-//go:nowritebarrier
+//
+//go:nowritebarrierrec
 func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
 	_g_ := getg()
 	c := &sigctxt{info, ctxt}
-- 
2.50.0