diff --git a/test-linuxcnc-source-link.sh b/test-linuxcnc-source-link.sh
index 6c1e1c4..e7b9cec 100755
--- a/test-linuxcnc-source-link.sh
+++ b/test-linuxcnc-source-link.sh
@@ -224,6 +224,12 @@ INI_FILE_NAME="$multi_spindle_modes_file" CNC_SIM_RS274_VAR="$var_file" \
 INI_FILE_NAME="$multi_spindle_modes_file" CNC_SIM_RS274_VAR="$var_file" \
     "$build_dir/linuxcnc_rs274_source_dump" tests/gcode/linuxcnc_multi_spindle_all_direction.ngc \
     >"$output_dir/cnc_sim_linuxcnc_source_multi_spindle_all_direction.json"
+# Source basis: LinuxCNC src/emc/rs274ngc/rs274ngc_pre.cc init reads
+# [TRAJ] SPINDLES from INI_FILE_NAME, and interp_convert.cc M5 without a $
+# selector stops every configured spindle.
+INI_FILE_NAME="$multi_spindle_modes_file" CNC_SIM_RS274_VAR="$var_file" \
+    "$build_dir/linuxcnc_rs274_source_dump" tests/gcode/linuxcnc_multi_spindle_default_stop.ngc \
+    >"$output_dir/cnc_sim_linuxcnc_source_multi_spindle_default_stop.json"
 CNC_SIM_RS274_VAR="$var_file" \
     "$build_dir/linuxcnc_rs274_source_dump" tests/gcode/linuxcnc_spindle_modes.ngc \
     >"$output_dir/cnc_sim_linuxcnc_source_spindle_modes.json"
@@ -1861,6 +1867,22 @@ if multi_spindle_all_direction_states != expected_multi_spindle_all_direction_st
         f"{multi_spindle_all_direction_states!r}"
     )
 
+multi_spindle_default_stop = json.loads((OUTPUT_DIR / "cnc_sim_linuxcnc_source_multi_spindle_default_stop.json").read_text())
+multi_spindle_default_stop_states = [
+    (event["line"], event["tool"], event["spindle"], event["reserved"])
+    for event in multi_spindle_default_stop
+    if event["type"] == "set-spindle" and event["line"] == 6
+]
+expected_multi_spindle_default_stop_states = [
+    (6, 0, 0, 0),
+    (6, 1, 0, 0),
+]
+if multi_spindle_default_stop_states != expected_multi_spindle_default_stop_states:
+    raise SystemExit(
+        "unexpected source-linked default M5 all-spindles stop states: "
+        f"{multi_spindle_default_stop_states!r}"
+    )
+
 spindle_modes = json.loads((OUTPUT_DIR / "cnc_sim_linuxcnc_source_spindle_modes.json").read_text())
 spindle_mode_states = [
     (event["line"], event["reserved"], event["feed"], event["tool"])
@@ -3789,6 +3811,7 @@ echo "dumped $output_dir/cnc_sim_linuxcnc_source_rtcp_controls.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_spindle_direction.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_multi_spindle_direction.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_multi_spindle_all_direction.json"
+echo "dumped $output_dir/cnc_sim_linuxcnc_source_multi_spindle_default_stop.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_spindle_modes.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_spindle_orient.json"
 echo "dumped $output_dir/cnc_sim_linuxcnc_source_multi_spindle_orient.json"
diff --git a/tests/gcode/linuxcnc_multi_spindle_default_stop.ngc b/tests/gcode/linuxcnc_multi_spindle_default_stop.ngc
new file mode 100644
index 0000000..2efd415
--- /dev/null
+++ b/tests/gcode/linuxcnc_multi_spindle_default_stop.ngc
@@ -0,0 +1,7 @@
+G21 G90 G17
+(Source basis: LinuxCNC src/emc/rs274ngc/rs274ngc_pre.cc init reads [TRAJ] SPINDLES from INI_FILE_NAME.)
+(Source basis: LinuxCNC src/emc/rs274ngc/interp_convert.cc M5 without $ stops all configured spindles.)
+S1200 $-1
+M3 $-1
+M5
+M30