diff --git a/src/pkg/runtime/darwin/thread.c b/src/pkg/runtime/darwin/thread.c
index e51d530196..6f64c08738 100644
--- a/src/pkg/runtime/darwin/thread.c
+++ b/src/pkg/runtime/darwin/thread.c
@@ -453,11 +453,13 @@ sigpanic(void)
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000)
 			panicstring("invalid memory address or nil pointer dereference");
-		break;
+		printf("unexpected fault address %p\n", g->sigcode1);
+		throw("fault");
 	case SIGSEGV:
 		if((g->sigcode0 == 0 || g->sigcode0 == SEGV_MAPERR) && g->sigcode1 < 0x1000)
 			panicstring("invalid memory address or nil pointer dereference");
-		break;
+		printf("unexpected fault address %p\n", g->sigcode1);
+		throw("fault");
 	case SIGFPE:
 		switch(g->sigcode0) {
 		case FPE_INTDIV:
diff --git a/src/pkg/runtime/freebsd/thread.c b/src/pkg/runtime/freebsd/thread.c
index 3340433122..c9c058c5ae 100644
--- a/src/pkg/runtime/freebsd/thread.c
+++ b/src/pkg/runtime/freebsd/thread.c
@@ -179,11 +179,13 @@ sigpanic(void)
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000)
 			panicstring("invalid memory address or nil pointer dereference");
-		break;
+		printf("unexpected fault address %p\n", g->sigcode1);
+		throw("fault");
 	case SIGSEGV:
 		if((g->sigcode0 == 0 || g->sigcode0 == SEGV_MAPERR) && g->sigcode1 < 0x1000)
 			panicstring("invalid memory address or nil pointer dereference");
-		break;
+		printf("unexpected fault address %p\n", g->sigcode1);
+		throw("fault");
 	case SIGFPE:
 		switch(g->sigcode0) {
 		case FPE_INTDIV:
diff --git a/src/pkg/runtime/linux/thread.c b/src/pkg/runtime/linux/thread.c
index a849125f94..47bf3428f7 100644
--- a/src/pkg/runtime/linux/thread.c
+++ b/src/pkg/runtime/linux/thread.c
@@ -279,11 +279,13 @@ sigpanic(void)
 	case SIGBUS:
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000)
 			panicstring("invalid memory address or nil pointer dereference");
-		break;
+		printf("unexpected fault address %p\n", g->sigcode1);
+		throw("fault");
 	case SIGSEGV:
 		if((g->sigcode0 == 0 || g->sigcode0 == SEGV_MAPERR) && g->sigcode1 < 0x1000)
 			panicstring("invalid memory address or nil pointer dereference");
-		break;
+		printf("unexpected fault address %p\n", g->sigcode1);
+		throw("fault");
 	case SIGFPE:
 		switch(g->sigcode0) {
 		case FPE_INTDIV: