runtime: fix traceback across morestack

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/12287043

diff --git a/src/pkg/runtime/asm_arm.s b/src/pkg/runtime/asm_arm.s
index 863d9a50647ad4c4c211bf0c252641f9f32e8e16..bdd37215b3ca350c2e2360d2c40b28ff78946bd3 100644 (file)
--- a/src/pkg/runtime/asm_arm.s
+++ b/src/pkg/runtime/asm_arm.s
@@ -204,6 +204,10 @@ TEXT runtime·morestack(SB),7,$-4-0
        MOVW    (g_sched+gobuf_sp)(g), SP
        BL      runtime·newstack(SB)
 
+       // Not reached, but make sure the return PC from the call to newstack
+       // is still in this function, and not the beginning of the next.
+       RET
+
 // Called from reflection library.  Mimics morestack,
 // reuses stack growth code to create a frame
 // with the desired args running the desired function.