From: Michael Pratt <mpratt@google.com>
Date: Thu, 14 Jul 2022 21:29:29 +0000 (-0400)
Subject: runtime: convert runningPanicDefers to atomic type
X-Git-Tag: go1.20rc1~1675
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=7666ec1c99b2f8c88b42fb5462510cafce120a6f;p=gostls13.git

runtime: convert runningPanicDefers to atomic type

For #53821.

Change-Id: Ib48a1f2ff85d667c86dbd0b7662efab5a0abd837
Reviewed-on: https://go-review.googlesource.com/c/go/+/419437
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
---

diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index 3783e3dede..a3e676fea4 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -837,7 +837,7 @@ func gopanic(e any) {
 	p.link = gp._panic
 	gp._panic = (*_panic)(noescape(unsafe.Pointer(&p)))
 
-	atomic.Xadd(&runningPanicDefers, 1)
+	runningPanicDefers.Add(1)
 
 	// By calculating getcallerpc/getcallersp here, we avoid scanning the
 	// gopanic frame (stack scanning is slow...)
@@ -917,7 +917,7 @@ func gopanic(e any) {
 				mcall(recovery)
 				throw("bypassed recovery failed") // mcall should not return
 			}
-			atomic.Xadd(&runningPanicDefers, -1)
+			runningPanicDefers.Add(-1)
 
 			// After a recover, remove any remaining non-started,
 			// open-coded defer entries, since the corresponding defers
@@ -1067,9 +1067,8 @@ func fatal(s string) {
 }
 
 // runningPanicDefers is non-zero while running deferred functions for panic.
-// runningPanicDefers is incremented and decremented atomically.
 // This is used to try hard to get a panic stack trace out when exiting.
-var runningPanicDefers uint32
+var runningPanicDefers atomic.Uint32
 
 // panicking is non-zero when crashing the program for an unrecovered panic.
 // panicking is incremented and decremented atomically.
@@ -1155,7 +1154,7 @@ func fatalpanic(msgs *_panic) {
 			// startpanic_m set panicking, which will
 			// block main from exiting, so now OK to
 			// decrement runningPanicDefers.
-			atomic.Xadd(&runningPanicDefers, -1)
+			runningPanicDefers.Add(-1)
 
 			printpanics(msgs)
 		}
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index cea7f37d13..33219419f9 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -256,10 +256,10 @@ func main() {
 	// another goroutine at the same time as main returns,
 	// let the other goroutine finish printing the panic trace.
 	// Once it does, it will exit. See issues 3934 and 20018.
-	if atomic.Load(&runningPanicDefers) != 0 {
+	if runningPanicDefers.Load() != 0 {
 		// Running deferred functions should not take long.
 		for c := 0; c < 1000; c++ {
-			if atomic.Load(&runningPanicDefers) == 0 {
+			if runningPanicDefers.Load() == 0 {
 				break
 			}
 			Gosched()