From patchwork Thu Jun 25 13:27:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colin King X-Patchwork-Id: 11625371 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5A803138C for ; Thu, 25 Jun 2020 13:27:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BD2320781 for ; Thu, 25 Jun 2020 13:27:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405059AbgFYN1k (ORCPT ); Thu, 25 Jun 2020 09:27:40 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:48403 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404872AbgFYN1k (ORCPT ); Thu, 25 Jun 2020 09:27:40 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1joRui-0000Py-C0; Thu, 25 Jun 2020 13:27:36 +0000 From: Colin King To: Marek Vasut , Michael Turquette , Stephen Boyd , Adam Ford , linux-clk@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH][next] clk: vc5: fix use of memory after it has been kfree'd Date: Thu, 25 Jun 2020 14:27:36 +0100 Message-Id: <20200625132736.88832-1-colin.king@canonical.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org 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 Reviewed-by: Luca Ceresoli --- 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; + } ret = of_clk_add_hw_provider(client->dev.of_node, vc5_of_clk_get, vc5); @@ -1029,6 +1013,9 @@ static int vc5_probe(struct i2c_client *client, const struct i2c_device_id *id) return 0; +err_clk_register: + dev_err(&client->dev, "unable to register %s\n", init.name); + kfree(init.name); /* clock framework made a copy of the name */ err_clk: if (vc5->chip_info->flags & VC5_HAS_INTERNAL_XTAL) clk_unregister_fixed_rate(vc5->pin_xin);