Save trace recorder state around VM event call.

Reported by Sergey Kaplun.

src/lj_trace.c

@@ -587,9 +587,11 @@ static TValue *trace_state(lua_State *L, lua_CFunction dummy, void *ud)
       trace_pendpatch(J, 0);
       setvmstate(J2G(J), RECORD);
       lj_vmevent_send_(L, RECORD,
-	/* Save/restore tmptv state for trace recorder. */
+	/* Save/restore state for trace recorder. */
 	TValue savetv = J2G(J)->tmptv;
 	TValue savetv2 = J2G(J)->tmptv2;
+	TraceNo parent = J->parent;
+	ExitNo exitno = J->exitno;
 	setintV(L->top++, J->cur.traceno);
 	setfuncV(L, L->top++, J->fn);
 	setintV(L->top++, J->pt ? (int32_t)proto_bcpos(J->pt, J->pc) : -1);
@@ -597,6 +599,8 @@ static TValue *trace_state(lua_State *L, lua_CFunction dummy, void *ud)
       ,
 	J2G(J)->tmptv = savetv;
 	J2G(J)->tmptv2 = savetv2;
+	J->parent = parent;
+	J->exitno = exitno;
       );
       lj_record_ins(J);
       break;