diff --git a/src/pkg/runtime/os_darwin.c b/src/pkg/runtime/os_darwin.c
index f226261..a1165dd 100644
--- a/src/pkg/runtime/os_darwin.c
+++ b/src/pkg/runtime/os_darwin.c
@@ -434,6 +434,9 @@
 void
 runtime·sigpanic(void)
 {
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	switch(g->sig) {
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000 || g->paniconfault) {
diff --git a/src/pkg/runtime/os_dragonfly.c b/src/pkg/runtime/os_dragonfly.c
index f96ea89..35a7de9 100644
--- a/src/pkg/runtime/os_dragonfly.c
+++ b/src/pkg/runtime/os_dragonfly.c
@@ -169,6 +169,9 @@
 void
 runtime·sigpanic(void)
 {
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	switch(g->sig) {
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000 || g->paniconfault) {
diff --git a/src/pkg/runtime/os_freebsd.c b/src/pkg/runtime/os_freebsd.c
index 7598b13..9a8de42 100644
--- a/src/pkg/runtime/os_freebsd.c
+++ b/src/pkg/runtime/os_freebsd.c
@@ -177,6 +177,9 @@
 void
 runtime·sigpanic(void)
 {
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	switch(g->sig) {
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000 || g->paniconfault) {
diff --git a/src/pkg/runtime/os_linux.c b/src/pkg/runtime/os_linux.c
index b4be940..8a94524 100644
--- a/src/pkg/runtime/os_linux.c
+++ b/src/pkg/runtime/os_linux.c
@@ -218,6 +218,9 @@
 void
 runtime·sigpanic(void)
 {
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	switch(g->sig) {
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000 || g->paniconfault) {
diff --git a/src/pkg/runtime/os_nacl.c b/src/pkg/runtime/os_nacl.c
index 3c5e487..3196e2c 100644
--- a/src/pkg/runtime/os_nacl.c
+++ b/src/pkg/runtime/os_nacl.c
@@ -247,6 +247,9 @@
 void
 runtime·sigpanic(void)
 {
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	// Native Client only invokes the exception handler for memory faults.
 	g->sig = SIGSEGV;
 	if(g->sigpc == 0)
diff --git a/src/pkg/runtime/os_netbsd.c b/src/pkg/runtime/os_netbsd.c
index f8ae309..7f4b972 100644
--- a/src/pkg/runtime/os_netbsd.c
+++ b/src/pkg/runtime/os_netbsd.c
@@ -237,6 +237,9 @@
 void
 runtime·sigpanic(void)
 {
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	switch(g->sig) {
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000 || g->paniconfault) {
diff --git a/src/pkg/runtime/os_openbsd.c b/src/pkg/runtime/os_openbsd.c
index 714f907..0eec795 100644
--- a/src/pkg/runtime/os_openbsd.c
+++ b/src/pkg/runtime/os_openbsd.c
@@ -214,6 +214,9 @@
 void
 runtime·sigpanic(void)
 {
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	switch(g->sig) {
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000 || g->paniconfault) {
diff --git a/src/pkg/runtime/os_plan9.c b/src/pkg/runtime/os_plan9.c
index af20ce8..b634fd7 100644
--- a/src/pkg/runtime/os_plan9.c
+++ b/src/pkg/runtime/os_plan9.c
@@ -352,6 +352,9 @@
 {
 	byte *p;
 
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	switch(g->sig) {
 	case SIGRFAULT:
 	case SIGWFAULT:
diff --git a/src/pkg/runtime/os_plan9_386.c b/src/pkg/runtime/os_plan9_386.c
index 04be91b..80d711f 100644
--- a/src/pkg/runtime/os_plan9_386.c
+++ b/src/pkg/runtime/os_plan9_386.c
@@ -71,9 +71,6 @@
 		runtime·exits(note+9); // Strip "go: exit " prefix.
 
 	if(flags & SigPanic) {
-		if(!runtime·canpanic(gp))
-			goto Throw;
-
 		// Copy the error string from sigtramp's stack into m->notesig so
 		// we can reliably access it from the panic routines.
 		runtime·memmove(m->notesig, note, len+1);
diff --git a/src/pkg/runtime/os_plan9_amd64.c b/src/pkg/runtime/os_plan9_amd64.c
index 7f4e118..b497056 100644
--- a/src/pkg/runtime/os_plan9_amd64.c
+++ b/src/pkg/runtime/os_plan9_amd64.c
@@ -79,9 +79,6 @@
 		runtime·exits(note+9); // Strip "go: exit " prefix.
 
 	if(flags & SigPanic) {
-		if(!runtime·canpanic(gp))
-			goto Throw;
-
 		// Copy the error string from sigtramp's stack into m->notesig so
 		// we can reliably access it from the panic routines.
 		runtime·memmove(m->notesig, note, len+1);
diff --git a/src/pkg/runtime/os_solaris.c b/src/pkg/runtime/os_solaris.c
index b8cd4d9..3575f69 100644
--- a/src/pkg/runtime/os_solaris.c
+++ b/src/pkg/runtime/os_solaris.c
@@ -209,6 +209,9 @@
 void
 runtime·sigpanic(void)
 {
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	switch(g->sig) {
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000 || g->paniconfault) {
diff --git a/src/pkg/runtime/os_windows.c b/src/pkg/runtime/os_windows.c
index 8cb6e15..4d5ea3b 100644
--- a/src/pkg/runtime/os_windows.c
+++ b/src/pkg/runtime/os_windows.c
@@ -346,6 +346,9 @@
 void
 runtime·sigpanic(void)
 {
+	if(!runtime·canpanic(g))
+		runtime·throw("unexpected signal during runtime execution");
+
 	switch(g->sig) {
 	case EXCEPTION_ACCESS_VIOLATION:
 		if(g->sigcode1 < 0x1000 || g->paniconfault) {
diff --git a/src/pkg/runtime/signal_386.c b/src/pkg/runtime/signal_386.c
index 70790fa0..70fcc6a 100644
--- a/src/pkg/runtime/signal_386.c
+++ b/src/pkg/runtime/signal_386.c
@@ -45,9 +45,6 @@
 
 	t = &runtime·sigtab[sig];
 	if(SIG_CODE0(info, ctxt) != SI_USER && (t->flags & SigPanic)) {
-		if(!runtime·canpanic(gp))
-			goto Throw;
-
 		// Make it look like a call to the signal func.
 		// Have to pass arguments out of band since
 		// augmenting the stack frame would break
@@ -94,7 +91,6 @@
 	if(!(t->flags & SigThrow))
 		return;
 
-Throw:
 	m->throwing = 1;
 	m->caughtsig = gp;
 	runtime·startpanic();
diff --git a/src/pkg/runtime/signal_amd64x.c b/src/pkg/runtime/signal_amd64x.c
index b217338..309bad3 100644
--- a/src/pkg/runtime/signal_amd64x.c
+++ b/src/pkg/runtime/signal_amd64x.c
@@ -54,9 +54,6 @@
 
 	t = &runtime·sigtab[sig];
 	if(SIG_CODE0(info, ctxt) != SI_USER && (t->flags & SigPanic)) {
-		if(!runtime·canpanic(gp))
-			goto Throw;
-
 		// Make it look like a call to the signal func.
 		// Have to pass arguments out of band since
 		// augmenting the stack frame would break
@@ -107,7 +104,6 @@
 	if(!(t->flags & SigThrow))
 		return;
 
-Throw:
 	m->throwing = 1;
 	m->caughtsig = gp;
 	runtime·startpanic();
diff --git a/src/pkg/runtime/signal_arm.c b/src/pkg/runtime/signal_arm.c
index 41997db..9b2a43d 100644
--- a/src/pkg/runtime/signal_arm.c
+++ b/src/pkg/runtime/signal_arm.c
@@ -52,9 +52,6 @@
 
 	t = &runtime·sigtab[sig];
 	if(SIG_CODE0(info, ctxt) != SI_USER && (t->flags & SigPanic)) {
-		if(!runtime·canpanic(gp))
-			goto Throw;
-
 		// Make it look like a call to the signal func.
 		// Have to pass arguments out of band since
 		// augmenting the stack frame would break
@@ -92,7 +89,6 @@
 	if(!(t->flags & SigThrow))
 		return;
 
-Throw:
 	m->throwing = 1;
 	m->caughtsig = gp;
 	if(runtime·panicking)	// traceback already printed