From 50104cc32a498f7517a51c8dc93106c51c7a54b4 Mon Sep 17 00:00:00 2001
From: Ondřej Surý <ondrej@sury.org>
Date: Wed, 20 Apr 2011 15:44:41 +0200
Subject: Imported Upstream version 2011.03.07.1

---
 src/pkg/runtime/runtime.c | 40 ++++++++++++++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 8 deletions(-)

(limited to 'src/pkg/runtime/runtime.c')

diff --git a/src/pkg/runtime/runtime.c b/src/pkg/runtime/runtime.c
index e3a20d48a..1a3653f10 100644
--- a/src/pkg/runtime/runtime.c
+++ b/src/pkg/runtime/runtime.c
@@ -3,12 +3,13 @@
 // license that can be found in the LICENSE file.
 
 #include "runtime.h"
+#include "stack.h"
 
 enum {
 	maxround = sizeof(uintptr),
 };
 
-int32	runtime·panicking	= 0;
+uint32	runtime·panicking;
 
 int32
 runtime·gotraceback(void)
@@ -21,14 +22,24 @@ runtime·gotraceback(void)
 	return runtime·atoi(p);
 }
 
+static Lock paniclk;
+
 void
-runtime·dopanic(int32 unused)
+runtime·startpanic(void)
 {
-	if(runtime·panicking) {
-		runtime·printf("double panic\n");
+	if(m->dying) {
+		runtime·printf("panic during panic\n");
 		runtime·exit(3);
 	}
-	runtime·panicking++;
+	m->dying = 1;
+	runtime·xadd(&runtime·panicking, 1);
+	runtime·lock(&paniclk);
+}
+
+void
+runtime·dopanic(int32 unused)
+{
+	static bool didothers;
 
 	if(g->sig != 0)
 		runtime·printf("\n[signal %x code=%p addr=%p pc=%p]\n",
@@ -37,10 +48,22 @@ runtime·dopanic(int32 unused)
 	runtime·printf("\n");
 	if(runtime·gotraceback()){
 		runtime·traceback(runtime·getcallerpc(&unused), runtime·getcallersp(&unused), 0, g);
-		runtime·tracebackothers(g);
+		if(!didothers) {
+			didothers = true;
+			runtime·tracebackothers(g);
+		}
 	}
-	
-	runtime·breakpoint();  // so we can grab it in a debugger
+	runtime·unlock(&paniclk);
+	if(runtime·xadd(&runtime·panicking, -1) != 0) {
+		// Some other m is panicking too.
+		// Let it print what it needs to print.
+		// Wait forever without chewing up cpu.
+		// It will exit when it's done.
+		static Lock deadlock;
+		runtime·lock(&deadlock);
+		runtime·lock(&deadlock);
+	}
+
 	runtime·exit(2);
 }
 
@@ -73,6 +96,7 @@ runtime·throwinit(void)
 void
 runtime·throw(int8 *s)
 {
+	runtime·startpanic();
 	runtime·printf("throw: %s\n", s);
 	runtime·dopanic(0);
 	*(int32*)0 = 0;	// not reached
-- 
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