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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 E58A3C2BBD5 for ; Thu, 3 Dec 2020 18:25:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1B172085B for ; Thu, 3 Dec 2020 18:25:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502046AbgLCSZR (ORCPT ); Thu, 3 Dec 2020 13:25:17 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:34072 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731594AbgLCSZK (ORCPT ); Thu, 3 Dec 2020 13:25:10 -0500 Received: from 1.general.cking.uk.vpn ([10.172.193.212]) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kktHG-0000p3-Ro; Thu, 03 Dec 2020 18:24:26 +0000 Subject: Re: media: i2c: add OV02A10 image sensor driver To: Andy Shevchenko Cc: Dongchun Zhu , Andy Shevchenko , Sakari Ailus , Mauro Carvalho Chehab , Matthias Brugger , linux-media , "linux-arm-kernel@lists.infradead.org" , "moderated list:ARM/Mediatek SoC support" , "linux-kernel@vger.kernel.org" References: <9af089ea-2532-68ac-5d22-97a669ccec91@canonical.com> From: Colin Ian King Message-ID: <8eb453c7-a221-e741-5fe5-655e59075f34@canonical.com> Date: Thu, 3 Dec 2020 18:24:26 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/12/2020 18:10, Andy Shevchenko wrote: > On Thu, Dec 3, 2020 at 8:03 PM Colin Ian King wrote: > >> Static analysis on linux-next with Coverity has detected an issue with >> the following commit: > > If you want to fix it properly, see my comments below... > >> 529 static int ov02a10_s_stream(struct v4l2_subdev *sd, int on) >> 530 { >> 531 struct ov02a10 *ov02a10 = to_ov02a10(sd); >> 532 struct i2c_client *client = >> v4l2_get_subdevdata(&ov02a10->subdev); >> >> 1. var_decl: Declaring variable ret without initializer. >> >> 533 int ret; >> 534 >> 535 mutex_lock(&ov02a10->mutex); >> 536 >> >> 2. Condition ov02a10->streaming == on, taking true branch. >> >> 537 if (ov02a10->streaming == on) >> >> 3. Jumping to label unlock_and_return. >> >> 538 goto unlock_and_return; >> 539 >> 540 if (on) { >> 541 ret = pm_runtime_get_sync(&client->dev); >> 542 if (ret < 0) { > >> 543 pm_runtime_put_noidle(&client->dev); >> 544 goto unlock_and_return; > > Instead of two above: > goto err_rpm_put; > >> 545 } >> 546 >> 547 ret = __ov02a10_start_stream(ov02a10); >> 548 if (ret) { >> 549 __ov02a10_stop_stream(ov02a10); >> 550 ov02a10->streaming = !on; >> 551 goto err_rpm_put; >> 552 } >> 553 } else { >> 554 __ov02a10_stop_stream(ov02a10); >> 555 pm_runtime_put(&client->dev); >> 556 } >> 557 >> 558 ov02a10->streaming = on; > > (1) > >> 559 mutex_unlock(&ov02a10->mutex); >> 560 >> 561 return 0; >> 562 >> 563 err_rpm_put: >> 564 pm_runtime_put(&client->dev); > >> 565 unlock_and_return: > > Should be moved to (1). > >> 566 mutex_unlock(&ov02a10->mutex); >> 567 >> >> Uninitialized scalar variable (UNINIT) >> 4. uninit_use: Using uninitialized value ret. >> >> 568 return ret; >> 569 } >> >> Variable ret has not been initialized, so the error return value is a >> garbage value. It should be initialized with some appropriate negative >> error code, or ret could be removed and the return should return a >> literal value of a error code. >> >> I was unsure what value is appropriate to fix this, so instead I'm >> reporting this issue. > Not sure I fully understand how that fixes it. Given that ret is currently not initialized when we hit: if (ov02a10->streaming == on) goto unlock_and_return; either we initialize ret to 0 at the start of the function, or do: if (ov02a10->streaming == on) { ret = 0; goto unlock_and_return; } (assuming the intention is to return zero for this specific case). Colin