diff --git a/src/c/stacks.d b/src/c/stacks.d
index ac39f7639..714ccc9f9 100644
--- a/src/c/stacks.d
+++ b/src/c/stacks.d
@@ -532,6 +532,12 @@ frs_overflow(void)              /* used as condition in list.d */
 ecl_frame_ptr
 _ecl_frs_push(register cl_env_ptr env, register cl_object val)
 {
+  /* We store a dummy tag first, to make sure that it is safe to
+   * interrupt this method with a call to ecl_unwind. Otherwise, a
+   * stray ECL_PROTECT_TAG will lead to segfaults. AO_store_full is
+   * needed to ensure that the CPU doesn't reorder the memory
+   * stores. */
+  AO_store_full((AO_t*)&(env->frs_top+1)->frs_val,(AO_t)ECL_DUMMY_TAG);
   ecl_frame_ptr output = ++env->frs_top;
   if (output >= env->frs_limit) {
     frs_overflow();
diff --git a/src/c/symbols_list.h b/src/c/symbols_list.h
index ffe8c65e3..5fc077709 100755
--- a/src/c/symbols_list.h
+++ b/src/c/symbols_list.h
@@ -74,6 +74,7 @@ cl_symbols[] = {
 {"T", CL_ORDINARY, NULL, -1, OBJNULL},
 {SYS_ "UNBOUND", SI_CONSTANT, si_unbound, 0, ECL_UNBOUND},
 {SYS_ "PROTECT-TAG", SI_ORDINARY, NULL, -1, OBJNULL},
+{SYS_ "DUMMY-TAG", SI_ORDINARY, NULL, -1, OBJNULL},
 {SYS_ "*RESTART-CLUSTERS*", SI_SPECIAL, NULL, -1, Cnil},
 {SYS_ "*HANDLER-CLUSTERS*", SI_SPECIAL, NULL, -1, Cnil},
 
diff --git a/src/c/symbols_list2.h b/src/c/symbols_list2.h
index acd1b8442..5c9f730ac 100644
--- a/src/c/symbols_list2.h
+++ b/src/c/symbols_list2.h
@@ -74,6 +74,7 @@ cl_symbols[] = {
 {"T",NULL},
 {SYS_ "UNBOUND","si_unbound"},
 {SYS_ "PROTECT-TAG",NULL},
+{SYS_ "DUMMY-TAG",NULL},
 {SYS_ "*RESTART-CLUSTERS*",NULL},
 {SYS_ "*HANDLER-CLUSTERS*",NULL},
 
diff --git a/src/h/object.h b/src/h/object.h
index c83ba0d9e..111d68d08 100644
--- a/src/h/object.h
+++ b/src/h/object.h
@@ -246,8 +246,9 @@ enum ecl_stype {                /*  symbol type  */
 #define ECL_T                   ((cl_object)(cl_symbols+1))
 #define ECL_UNBOUND             ((cl_object)(cl_symbols+2))
 #define ECL_PROTECT_TAG         ((cl_object)(cl_symbols+3))
-#define ECL_RESTART_CLUSTERS    ((cl_object)(cl_symbols+4))
-#define ECL_HANDLER_CLUSTERS    ((cl_object)(cl_symbols+5))
+#define ECL_DUMMY_TAG           ((cl_object)(cl_symbols+4))
+#define ECL_RESTART_CLUSTERS    ((cl_object)(cl_symbols+5))
+#define ECL_HANDLER_CLUSTERS    ((cl_object)(cl_symbols+6))
 #define ECL_NO_TL_BINDING       ((cl_object)(1 << ECL_TAG_BITS))
 
 struct ecl_symbol {