livepatch: fix deferred module patching order

When applying multiple patches to a module, if the module is loaded
after the patches are loaded, the patches are applied in reverse order:

  $ insmod patch1.ko
  [   43.172992] livepatch: enabling patch 'patch1'

  $ insmod patch2.ko
  [   46.571563] livepatch: enabling patch 'patch2'

  $ modprobe nfsd
  [   52.888922] livepatch: applying patch 'patch2' to loading module 'nfsd'
  [   52.899847] livepatch: applying patch 'patch1' to loading module 'nfsd'

Fix the loading order by storing the klp_patches list in queue order.

Signed-off-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

kernel/livepatch/core.c

@@ -739,7 +739,7 @@ static int klp_init_patch(struct klp_patch *patch)
 			goto free;
 	}
 
-	list_add(&patch->list, &klp_patches);
+	list_add_tail(&patch->list, &klp_patches);
 
 	mutex_unlock(&klp_mutex);