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 X-Spam-Level: X-Spam-Status: No, score=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AD06C433E3 for ; Tue, 21 Jul 2020 10:10:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 017A220771 for ; Tue, 21 Jul 2020 10:10:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729097AbgGUKKL (ORCPT ); Tue, 21 Jul 2020 06:10:11 -0400 Received: from hostingweb31-40.netsons.net ([89.40.174.40]:51349 "EHLO hostingweb31-40.netsons.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726415AbgGUKKL (ORCPT ); Tue, 21 Jul 2020 06:10:11 -0400 Received: from [78.134.114.177] (port=47970 helo=[192.168.77.67]) by hostingweb31.netsons.net with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1jxpDs-000C6e-Eh; Tue, 21 Jul 2020 12:10:08 +0200 Subject: Re: [PATCH][next] clk: vc5: fix use of memory after it has been kfree'd To: Colin King , Marek Vasut , Michael Turquette , Stephen Boyd , Adam Ford , linux-clk@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200625132736.88832-1-colin.king@canonical.com> From: Luca Ceresoli Message-ID: Date: Tue, 21 Jul 2020 12:10:07 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200625132736.88832-1-colin.king@canonical.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - hostingweb31.netsons.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lucaceresoli.net X-Get-Message-Sender-Via: hostingweb31.netsons.net: authenticated_id: luca@lucaceresoli.net X-Authenticated-Sender: hostingweb31.netsons.net: luca@lucaceresoli.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Colin, On 25/06/20 15:27, Colin King wrote: > From: Colin Ian King > > There are a several places where printing an error message of > init.name occurs after init.name has been kfree'd. Also the failure > message is duplicated each time in the code. Fix this by adding > a registration error failure path for these cases, moving the > duplicated error messages to one common point and kfree'ing init.name > only after it has been used. > > Changes also shrink the object code size by 171 bytes (x86-64, gcc 9.3): > > Before: > text data bss dec hex filename > 21057 3960 64 25081 61f9 drivers/clk/clk-versaclock5.o > > After: > text data bss dec hex filename > 20886 3960 64 24910 614e drivers/clk/clk-versaclock5.o > > Addresses-Coverity: ("Use after free") > Fixes: f491276a5168 ("clk: vc5: Allow Versaclock driver to support multiple instances") > > Signed-off-by: Colin Ian King Woah, good catch! > --- > drivers/clk/clk-versaclock5.c | 51 +++++++++++++---------------------- > 1 file changed, 19 insertions(+), 32 deletions(-) > > diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c > index 9a5fb3834b9a..1d8ee4b8b1f5 100644 > --- a/drivers/clk/clk-versaclock5.c > +++ b/drivers/clk/clk-versaclock5.c > @@ -882,11 +882,9 @@ static int vc5_probe(struct i2c_client *client, const struct i2c_device_id *id) > init.parent_names = parent_names; > vc5->clk_mux.init = &init; > ret = devm_clk_hw_register(&client->dev, &vc5->clk_mux); > + if (ret) > + goto err_clk_register; > kfree(init.name); /* clock framework made a copy of the name */ > - if (ret) { > - dev_err(&client->dev, "unable to register %s\n", init.name); > - goto err_clk; > - } > > if (vc5->chip_info->flags & VC5_HAS_PFD_FREQ_DBL) { > /* Register frequency doubler */ > @@ -900,12 +898,9 @@ static int vc5_probe(struct i2c_client *client, const struct i2c_device_id *id) > init.num_parents = 1; > vc5->clk_mul.init = &init; > ret = devm_clk_hw_register(&client->dev, &vc5->clk_mul); > + if (ret) > + goto err_clk_register; > kfree(init.name); /* clock framework made a copy of the name */ > - if (ret) { > - dev_err(&client->dev, "unable to register %s\n", > - init.name); > - goto err_clk; > - } > } > > /* Register PFD */ > @@ -921,11 +916,9 @@ static int vc5_probe(struct i2c_client *client, const struct i2c_device_id *id) > init.num_parents = 1; > vc5->clk_pfd.init = &init; > ret = devm_clk_hw_register(&client->dev, &vc5->clk_pfd); > + if (ret) > + goto err_clk_register; > kfree(init.name); /* clock framework made a copy of the name */ > - if (ret) { > - dev_err(&client->dev, "unable to register %s\n", init.name); > - goto err_clk; > - } > > /* Register PLL */ > memset(&init, 0, sizeof(init)); > @@ -939,11 +932,9 @@ static int vc5_probe(struct i2c_client *client, const struct i2c_device_id *id) > vc5->clk_pll.vc5 = vc5; > vc5->clk_pll.hw.init = &init; > ret = devm_clk_hw_register(&client->dev, &vc5->clk_pll.hw); > + if (ret) > + goto err_clk_register; > kfree(init.name); /* clock framework made a copy of the name */ > - if (ret) { > - dev_err(&client->dev, "unable to register %s\n", init.name); > - goto err_clk; > - } > > /* Register FODs */ > for (n = 0; n < vc5->chip_info->clk_fod_cnt; n++) { > @@ -960,12 +951,9 @@ static int vc5_probe(struct i2c_client *client, const struct i2c_device_id *id) > vc5->clk_fod[n].vc5 = vc5; > vc5->clk_fod[n].hw.init = &init; > ret = devm_clk_hw_register(&client->dev, &vc5->clk_fod[n].hw); > + if (ret) > + goto err_clk_register; > kfree(init.name); /* clock framework made a copy of the name */ > - if (ret) { > - dev_err(&client->dev, "unable to register %s\n", > - init.name); > - goto err_clk; > - } > } > > /* Register MUX-connected OUT0_I2C_SELB output */ > @@ -981,11 +969,9 @@ static int vc5_probe(struct i2c_client *client, const struct i2c_device_id *id) > vc5->clk_out[0].vc5 = vc5; > vc5->clk_out[0].hw.init = &init; > ret = devm_clk_hw_register(&client->dev, &vc5->clk_out[0].hw); > - kfree(init.name); /* clock framework made a copy of the name */ > - if (ret) { > - dev_err(&client->dev, "unable to register %s\n", init.name); > - goto err_clk; > - } > + if (ret) > + goto err_clk_register; > + kfree(init.name); /* clock framework made a copy of the name */ > > /* Register FOD-connected OUTx outputs */ > for (n = 1; n < vc5->chip_info->clk_out_cnt; n++) { > @@ -1008,17 +994,15 @@ static int vc5_probe(struct i2c_client *client, const struct i2c_device_id *id) > vc5->clk_out[n].vc5 = vc5; > vc5->clk_out[n].hw.init = &init; > ret = devm_clk_hw_register(&client->dev, &vc5->clk_out[n].hw); > + if (ret) > + goto err_clk_register; > kfree(init.name); /* clock framework made a copy of the name */ > - if (ret) { > - dev_err(&client->dev, "unable to register %s\n", > - init.name); > - goto err_clk; > - } > > /* Fetch Clock Output configuration from DT (if specified) */ > ret = vc5_get_output_config(client, &vc5->clk_out[n]); > if (ret) > goto err_clk; > + > } Stray newline. With it possibly fixed: Reviewed-by: Luca Ceresoli -- Luca