* closure, in which case we must enter the blackhole on return rather
* than continuing to evaluate the now-defunct closure.
*/
- STK_CHK_NP(WDS(Words) + SIZEOF_StgUpdateFrame);
+ STK_CHK_NP(WDS(Words) + SIZEOF_StgUpdateFrame + WDS(AP_STACK_SPLIM));
+ /* ensure there is at least AP_STACK_SPLIM words of headroom available
+ * after unpacking the AP_STACK. See bug #1466 */
PUSH_UPD_FRAME(Sp - SIZEOF_StgUpdateFrame, R1);
Sp = Sp - SIZEOF_StgUpdateFrame - WDS(Words);