commit 43732809b16af59e494a1055dd4dbe982122ca80
Author: Andriy Gapon <avg@icyb.net.ua>
Date:   Wed Dec 19 23:27:46 2012 +0200

    [wip][experiment] kernel linker: register kernel modules before preloaded modules...
    
    Also, skip adding sysinit and sysctl stuff from preloaded modules if module
    registration fails.
    
    This should result in much saner behavior if a module is present in both
    the kernel and a preloaded file.
    Perhaps, the original intent was to allow the preloaded files to override
    modules present in kernel, but that was extremly fragile because of double
    sysinit registration.

diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c
index b3ab4df..10008ab 100644
--- a/sys/kern/kern_linker.c
+++ b/sys/kern/kern_linker.c
@@ -365,6 +365,7 @@ linker_file_register_modules(linker_file_t lf)
 	return (first_error);
 }
 
+#if 0
 static void
 linker_init_kernel_modules(void)
 {
@@ -374,6 +375,7 @@ linker_init_kernel_modules(void)
 
 SYSINIT(linker_kernel, SI_SUB_KLD, SI_ORDER_ANY, linker_init_kernel_modules,
     0);
+#endif
 
 static int
 linker_load_file(const char *filename, linker_file_t *result)
@@ -1599,7 +1601,11 @@ restart:
 		printf("KLD file %s is missing dependencies\n", lf->filename);
 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 	}
-
+#if 1
+	error = linker_file_register_modules(linker_kernel_file);
+	if (error)
+		printf("linker_file_register_modules(linker_kernel_file) failed: %d\n", error);
+#endif
 	/*
 	 * We made it. Finish off the linking in the order we determined.
 	 */
@@ -1648,7 +1654,12 @@ restart:
 			    lf->filename);
 			goto fail;
 		}
-		linker_file_register_modules(lf);
+		error = linker_file_register_modules(lf);
+		if (error) {
+			printf("KLD file %s - failed to register modules: %d\n",
+			    lf->filename, error);
+			goto fail;
+		}
 		if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
 		    &si_stop, NULL) == 0)
 			sysinit_add(si_start, si_stop);