diff --git a/config/zfs-build.m4 b/config/zfs-build.m4
index a8609b8299b3..17cc80462c76 100644
--- a/config/zfs-build.m4
+++ b/config/zfs-build.m4
@@ -45,10 +45,11 @@ AC_DEFUN([ZFS_AC_DEBUG], [
 
 AC_DEFUN([ZFS_AC_DEBUGINFO_KERNEL], [
 	KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS CONFIG_DEBUG_INFO=y"
+	KERNELCPPFLAGS="${KERNELCPPFLAGS} -fno-inline"
 ])
 
 AC_DEFUN([ZFS_AC_DEBUGINFO_USER], [
-	DEBUG_CFLAGS="$DEBUG_CFLAGS -g"
+	DEBUG_CFLAGS="${DEBUG_CFLAGS} -g -fno-inline"
 ])
 
 AC_DEFUN([ZFS_AC_DEBUGINFO], [