Clear the saved register locations when processing the last frame dur…

…ing precise stack scanning, the registers save info is not precise for the last frame.

mono/mini/mini-gc.c

@@ -801,6 +801,18 @@ conservative_pass (TlsData *tls, guint8 *stack_start, guint8 *stack_end)
 			}
 			DEBUG (fprintf (logfile, "\t <Last frame>\n"));
 			last = FALSE;
+			/*
+			 * new_reg_locations is not precise when a method is interrupted during its epilog, so clear it.
+			 */
+			for (i = 0; i < MONO_MAX_IREGS; ++i) {
+				if (reg_locations [i]) {
+					DEBUG (fprintf (logfile, "\tscan saved reg %s location %p.\n", mono_arch_regname (i), reg_locations [i]));
+					mono_gc_conservatively_scan_area (reg_locations [i], (char*)reg_locations [i] + SIZEOF_SLOT);
+					scanned_registers += SIZEOF_SLOT;
+				}
+				reg_locations [i] = NULL;
+				new_reg_locations [i] = NULL;
+			}
 			continue;
 		}