From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 323C5C00144 for ; Fri, 29 Jul 2022 06:53:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235212AbiG2Gxt (ORCPT ); Fri, 29 Jul 2022 02:53:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235153AbiG2GxW (ORCPT ); Fri, 29 Jul 2022 02:53:22 -0400 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6AACE81B00 for ; Thu, 28 Jul 2022 23:53:15 -0700 (PDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4LvJBG0jjkz4x1Y; Fri, 29 Jul 2022 16:53:10 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1659077590; bh=mMQHa95tZrtKAkKeRbCcHdd7SVD3uqX6L7aTavd4BmI=; h=From:To:Subject:In-Reply-To:References:Date:From; b=gokuqtaqlk17LP6I/P2clgOWiapPyjljq5Fa/jnOMj8Ln7tdwUAC0mIq6pqLZv4aO lMg02ahMBupC9gROCF1HCPi23mzBTxYMxU2kjZi/4L5TH54rktOb7l8EMpEar1e77w PCOlMuj6i98zKM10riGf3w100QnM/4j1AQDycpU8CyEvPP13IgfxiThCvn635/5SFd KnCuaUkSRLpBvu91Yevu9mtCwZzU5XNdzKkqyoSXiJ7tPQ8Q2t9dD/muO063u0lmAl 30zdzIfNi7CXYXcjt//J/A4IsvnN44+o3KJadZFs/01KWsz3JWw+TbN/60NpCe8HoM OCQ7kVw2QyWAw== From: Michael Ellerman To: Miaoqian Lin , Scott Wood , Benjamin Herrenschmidt , Paul Mackerras , Christophe Leroy , Miaoqian Lin , Nick Child , Nate Case , Kumar Gala , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] powerpc/85xx: Fix reference leak in xes_mpc85xx_setup_arch In-Reply-To: <20220603121752.23548-1-linmq006@gmail.com> References: <20220603121752.23548-1-linmq006@gmail.com> Date: Fri, 29 Jul 2022 16:53:06 +1000 Message-ID: <87pmhobeb1.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Miaoqian Lin writes: > of_find_node_by_path() returns remote device nodepointer with > refcount incremented, we should use of_node_put() on it when done. > Add missing of_node_put() to avoid refcount leak. > > Fixes: 3038acf9091f ("powerpc/85xx: Add platform support for X-ES MPC85xx boards") > Signed-off-by: Miaoqian Lin > --- > changes in v2: > - update Fixes tag. > v1 Link: https://lore.kernel.org/all/20220603120907.19999-1-linmq006@gmail.com > --- > arch/powerpc/platforms/85xx/xes_mpc85xx.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/powerpc/platforms/85xx/xes_mpc85xx.c b/arch/powerpc/platforms/85xx/xes_mpc85xx.c > index 5836e4ecb7a0..93f67b430714 100644 > --- a/arch/powerpc/platforms/85xx/xes_mpc85xx.c > +++ b/arch/powerpc/platforms/85xx/xes_mpc85xx.c > @@ -130,6 +130,8 @@ static void __init xes_mpc85xx_setup_arch(void) > mpc85xx_smp_init(); > > fsl_pci_assign_primary(); > + > + of_node_put(root); > } For context, here is the full function: static void __init xes_mpc85xx_setup_arch(void) { struct device_node *root; const char *model = "Unknown"; root = of_find_node_by_path("/"); if (root == NULL) return; model = of_get_property(root, "model", NULL); printk(KERN_INFO "X-ES MPC85xx-based single-board computer: %s\n", model + strlen("xes,")); xes_mpc85xx_fixups(); mpc85xx_smp_init(); fsl_pci_assign_primary(); } So yes it's missing an of_node_put(root). But rather than add the of_node_put(), it would be simpler to just use of_root directly, then it doesn't need an of_node_put() at all. But then look closer. To begin with model is assigned "Unknown", but then unconditionally overwritten by the of_get_property() call. So that's a waste of space. And then if there's no model property of_get_property() will return NULL, and then the model + strlen("xes,") would oops. And all of that just to print the model at boot, which is not really necessary, anyone who cares can look it up in /proc/device-tree after the system has booted. So please just remove the lookup and printing of model entirely. cheers