diff --git a/common.mk b/common.mk
index 916484a6fec..53e832c6370 100644
--- a/common.mk
+++ b/common.mk
@@ -1975,7 +1975,9 @@ gc/distclean gc/realclean::
 
 modular-gc-precheck:
 modular-gc: probes.h gc/Makefile
-	$(Q) $(RUNRUBY) $(srcdir)/ext/extmk.rb \
+	$(Q) DTRACE='$(DTRACE)' DTRACE_EXT='$(DTRACE_EXT)' \
+		DTRACE_OBJ='$(DTRACE_OBJ)' DTRACE_REBUILD='$(DTRACE_REBUILD)' \
+		$(RUNRUBY) $(srcdir)/ext/extmk.rb \
 		$(SCRIPT_ARGS) \
 		--make='$(MAKE)' --make-flags="V=$(V) MINIRUBY='$(MINIRUBY)'" \
 		--gnumake=$(gnumake) --extflags="$(EXTLDFLAGS)" \
diff --git a/gc/default/default.c b/gc/default/default.c
index 27b9646d975..611f404fbb4 100644
--- a/gc/default/default.c
+++ b/gc/default/default.c
@@ -34,9 +34,7 @@
 #include "gc/gc.h"
 #include "gc/gc_impl.h"
 
-#ifndef BUILDING_MODULAR_GC
-# include "probes.h"
-#endif
+#include "probes.h"
 
 #ifdef BUILDING_MODULAR_GC
 # define RB_DEBUG_COUNTER_INC(_name) ((void)0)
@@ -8940,12 +8938,8 @@ gc_prof_timer_stop(rb_objspace_t *objspace)
     }
 }
 
-#ifdef BUILDING_MODULAR_GC
-# define RUBY_DTRACE_GC_HOOK(name)
-#else
-# define RUBY_DTRACE_GC_HOOK(name) \
+#define RUBY_DTRACE_GC_HOOK(name) \
     do {if (RUBY_DTRACE_GC_##name##_ENABLED()) RUBY_DTRACE_GC_##name();} while (0)
-#endif
 
 static inline void
 gc_prof_mark_timer_start(rb_objspace_t *objspace)
diff --git a/gc/extconf_base.rb b/gc/extconf_base.rb
index 2a224b9b0e3..4a99a809105 100644
--- a/gc/extconf_base.rb
+++ b/gc/extconf_base.rb
@@ -4,11 +4,49 @@ require "mkmf"
 
 srcdir = File.join(__dir__, "..")
 $INCFLAGS << " -I#{srcdir}"
-
 $CPPFLAGS << " -DBUILDING_MODULAR_GC"
 
 append_cflags("-fPIC")
 
+DTRACE_RULES = <<~MAKE
+
+  probes.stamp: $(GC_DTRACE_OBJS)
+  	$(Q) if test -f $@ -o -f $(GC_DTRACE_OBJ); then \
+  	  $(RM) $(GC_DTRACE_OBJS) $@; \
+  	  $(ECHO) rebuilding objects which were modified by "dtrace -G"; \
+  	  $(MAKE) $(GC_DTRACE_OBJS); \
+  	fi
+  	$(Q) touch $@
+
+  $(GC_DTRACE_OBJ): $(top_srcdir)/probes.d $(GC_DTRACE_REBUILD:yes=probes.stamp)
+  	$(ECHO) processing GC probes in object files
+  	$(Q) CC="$(CC)" CFLAGS="$(CFLAGS) $(INCFLAGS) $(CPPFLAGS)" $(GC_DTRACE) -G -C $(INCFLAGS) -s $(top_srcdir)/probes.d -o $@ $(GC_DTRACE_OBJS)
+MAKE
+
 def create_gc_makefile(name, &block)
-  create_makefile("librubygc.#{name}", &block)
+  dtrace_obj = ENV.fetch("DTRACE_OBJ", "")
+  dtrace_enabled = (name == "default" && !dtrace_obj.empty?)
+
+  if name == "default"
+    $INCFLAGS << " -I$(topdir)"
+    $headers << "$(topdir)/probes.h"
+    $cleanfiles << "probes.stamp"
+  end
+
+  create_makefile("librubygc.#{name}") do |conf|
+    conf = block.call(conf) if block
+    next conf unless dtrace_enabled
+
+    gc_objs = $objs.join(" ")
+    conf = Array(conf).join.sub(/^OBJS = .*$/, "OBJS = #{gc_objs} #{dtrace_obj}")
+    conf + <<~MAKE
+
+      GC_DTRACE = #{ENV.fetch("DTRACE")}
+      GC_DTRACE_OBJ = #{dtrace_obj}
+      GC_DTRACE_OBJS = #{gc_objs}
+      GC_DTRACE_REBUILD = #{ENV.fetch("DTRACE_REBUILD", "")}
+    MAKE
+  end
+
+  File.write("Makefile", DTRACE_RULES, mode: "ab") if dtrace_enabled
 end
diff --git a/test/dtrace/helper.rb b/test/dtrace/helper.rb
index 9e8c7ecd52c..4fd218e5394 100644
--- a/test/dtrace/helper.rb
+++ b/test/dtrace/helper.rb
@@ -115,7 +115,7 @@ module DTrace
       IO.popen(cmd, err: [:child, :out], &:readlines)
     end
 
-    def trap_probe d_program, ruby_program
+    def trap_probe d_program, ruby_program, env: {}
       if Hash === d_program
         d_program = d_program[IMPL] or
           omit "#{d_program} not implemented for #{IMPL}"
@@ -132,15 +132,17 @@ module DTrace
 
       d_path  = d.path
       rb_path = rb.path
-      cmd = "#{RUBYBIN} --disable=gems -I#{INCLUDE} #{rb_path}"
+      ruby_env = env
+      env_prefix = ruby_env.map {|key, val| "#{key}=#{val}" }
+      cmd = [*env_prefix, "#{RUBYBIN} --disable=gems -I#{INCLUDE} #{rb_path}"].join(" ")
       if IMPL == :stap
         cmd = %W(stap #{d_path} -c #{cmd})
       else
         cmd = [*DTRACE_CMD, "-q", "-s", d_path, "-c", cmd ]
       end
       if sudo = @@sudo
-        NEEDED_ENVS.each do |name|
-          if val = ENV[name]
+        (NEEDED_ENVS + ruby_env.keys).uniq.each do |name|
+          if val = ruby_env[name] || ENV[name]
             cmd.unshift("#{name}=#{val}")
           end
         end
diff --git a/test/dtrace/test_gc_modular.rb b/test/dtrace/test_gc_modular.rb
new file mode 100644
index 00000000000..68665c78139
--- /dev/null
+++ b/test/dtrace/test_gc_modular.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: false
+require_relative 'helper'
+
+module DTrace
+  class TestModularGC < TestCase
+    MODULAR_GC_DIR = RbConfig::CONFIG["modular_gc_dir"]
+    DLEXT = RbConfig::CONFIG["DLEXT"]
+    DEFAULT_GC = MODULAR_GC_DIR && File.join(MODULAR_GC_DIR, "librubygc.default.#{DLEXT}")
+
+    def setup
+      super
+      omit "Ruby was not configured with --with-modular-gc" if MODULAR_GC_DIR.nil? || MODULAR_GC_DIR.empty?
+      omit "default modular GC is not installed" unless DEFAULT_GC && File.file?(DEFAULT_GC)
+    end
+
+    %w[
+      gc-mark-begin
+      gc-mark-end
+      gc-sweep-begin
+      gc-sweep-end
+    ].each do |probe_name|
+      define_method(:"test_modular_#{probe_name.gsub(/-/, '_')}") do
+        probe = "ruby$target:::#{probe_name} { printf(\"#{probe_name}\\n\"); }"
+
+        trap_probe(probe, ruby_program, env: {"RUBY_GC_LIBRARY" => "default"}) do |_, _, saw|
+          assert_operator saw.length, :>, 0
+        end
+      end
+    end
+
+    private
+
+    def ruby_program
+      "100000.times { Object.new }"
+    end
+  end
+end if defined?(DTrace::TestCase)