diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 13ec3e96650c..69d74661d3d5 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -83,7 +83,17 @@ MODPOST += -e
 
 input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS)
 output-symdump := $(KBUILD_EXTMOD)/Module.symvers
-module_srcpath := $(KBUILD_EXTMOD)
+
+# Get the external module's source path. KBUILD_EXTMOD could either be an
+# absolute path or relative path from $(srctree). This makes sure that we
+# aren't using a relative path from a separate working directory (O= or
+# KBUILD_OUTPUT) since that may not be the actual module's SCM project path. So
+# check the path relative to $(srctree) first.
+ifneq ($(realpath $(srctree)/$(KBUILD_EXTMOD) 2>/dev/null),)
+	module_srcpath := $(srctree)/$(KBUILD_EXTMOD)
+else
+	module_srcpath := $(KBUILD_EXTMOD)
+endif
 
 endif