Merge branch 'bjorn/erts/fix-wrong-class/ERIERL-367/OTP-15834' into maint

* bjorn/erts/fix-wrong-class/ERIERL-367/OTP-15834:
  Fix sticky class in exception

2 files changed, 34 insertions, 3 deletions

diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index bae64afb97..07c16e3415 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -414,6 +414,7 @@ static Eterm add_stacktrace(Process* c_p, Eterm Value, Eterm exc);
 static void save_stacktrace(Process* c_p, BeamInstr* pc, Eterm* reg,
 			    ErtsCodeMFA *bif_mfa, Eterm args);
 static struct StackTrace * get_trace_from_exc(Eterm exc);
+static Eterm *get_freason_ptr_from_exc(Eterm exc);
 static Eterm make_arglist(Process* c_p, Eterm* reg, int a);
 
 void
@@ -1902,6 +1903,25 @@ static int is_raised_exc(Eterm exc) {
     }
 }
 
+static Eterm *get_freason_ptr_from_exc(Eterm exc) {
+    static Eterm dummy_freason;
+    struct StackTrace* s;
+
+    if (exc == NIL) {
+        /*
+         * Is is not exactly clear when exc can be NIL. Probably only
+         * when the exception has been generated from native code.
+         * Return a pointer to an Eterm that can be safely written and
+         * ignored.
+         */
+	return &dummy_freason;
+    } else {
+	ASSERT(is_list(exc));
+        s = (struct StackTrace *) big_val(CDR(list_val(exc)));
+        return &s->freason;
+    }
+}
+
 /*
  * Creating a list with the argument registers
  */
diff --git a/erts/emulator/beam/instrs.tab b/erts/emulator/beam/instrs.tab
index 462ee77e6f..7cffe7fb5c 100644
--- a/erts/emulator/beam/instrs.tab
+++ b/erts/emulator/beam/instrs.tab
@@ -1064,19 +1064,30 @@ raw_raise() {
     Eterm class = x(0);
     Eterm value = x(1);
     Eterm stacktrace = x(2);
+    Eterm* freason_ptr;
+
+    /*
+     * Note that the i_raise instruction will override c_p->freason
+     * with the freason field stored inside the StackTrace struct in
+     * ftrace. Therefore, we must take care to store the class both
+     * inside the StackTrace struct and in c_p->freason (important if
+     * the class is different from the class of the original
+     * exception).
+     */
+    freason_ptr = get_freason_ptr_from_exc(stacktrace);
 
     if (class == am_error) {
-        c_p->freason = EXC_ERROR & ~EXF_SAVETRACE;
+        *freason_ptr = c_p->freason = EXC_ERROR & ~EXF_SAVETRACE;
         c_p->fvalue = value;
         c_p->ftrace = stacktrace;
         goto find_func_info;
     } else if (class == am_exit) {
-        c_p->freason = EXC_EXIT & ~EXF_SAVETRACE;
+        *freason_ptr = c_p->freason = EXC_EXIT & ~EXF_SAVETRACE;
         c_p->fvalue = value;
         c_p->ftrace = stacktrace;
         goto find_func_info;
     } else if (class == am_throw) {
-        c_p->freason = EXC_THROWN & ~EXF_SAVETRACE;
+        *freason_ptr = c_p->freason = EXC_THROWN & ~EXF_SAVETRACE;
         c_p->fvalue = value;
         c_p->ftrace = stacktrace;
         goto find_func_info;