From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CAN01-TO1-obe.outbound.protection.outlook.com (mail-eopbgr670056.outbound.protection.outlook.com [40.107.67.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2002270 for ; Tue, 8 Jun 2021 06:40:29 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=hyzt+nbQe3K1JyIWl+b/8gF/hqgO7zNtpRk9FM8F+Oiq8aF/0NCZlyZ4zZZqSWCsZ7aGhe88+tKTwxL4HJkWRl9dtYhavEAhlJYYkjEbXrmJCnw5+dTFs/p1Waf98btUrBu/qv1x1dQohTr3PoszlVx/6Qo7UmPPUunino/xGqQBZsMhizkeFFaooDfQTX3QHtnk32vx4TN5MbQmk4BjgNBHYDfPtBMT0pvqFH/9HIHQpRAuTXSQETSlcVq7padUlTFs9r8MjjBSptvht1mcmheye9iCyb8cq670QjSNdxG6P0uU1Dfg4YlYVO29gyWJVMyMuLiMmWyfs8N9jfd6dw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=3E88rt/rcU8KJQzYrauX2KMCvgO32lij5xymqVMBYAU=; b=dPl5T/1b6ENH4wX7kUF0dID80y13NfHlcauB+ko1xAbC95FnJo9gFM3CataL7nLi8wXXCAxV51cErZjNCfxWzrUpAz9r1JiAjupYbR0VwSkqhPMzBqIxExdQ84NCxqU+pbinT37Xckt/181f1WggJ59s7Uw/kn8wavbYMSN7toV5FO5tkwT+x1Glgfi66m64RoaXlznn0KTnwXj3tAVz6BE/8EWmz1bS6gb10RAyfE2DhMjH/ShNXXfHQHVxSgpE81Xy2/sxs2Dde+V7g09z/FfIr1YMqdzqyw7A/YmC1BJLFzBMYu1peJ1OcGAsKRsIHLt5AwFBWjI3LHqWsUSnhg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=ucalgary.ca; dmarc=pass action=none header.from=ucalgary.ca; dkim=pass header.d=ucalgary.ca; arc=none Authentication-Results: lists.linux.dev; dkim=none (message not signed) header.d=none;lists.linux.dev; dmarc=none action=none header.from=ucalgary.ca; Received: from YQXPR01MB3302.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c00:4a::23) by YQBPR0101MB4682.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c01:15::23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4195.29; Tue, 8 Jun 2021 06:40:28 +0000 Received: from YQXPR01MB3302.CANPRD01.PROD.OUTLOOK.COM ([fe80::90eb:8466:4635:4b35]) by YQXPR01MB3302.CANPRD01.PROD.OUTLOOK.COM ([fe80::90eb:8466:4635:4b35%7]) with mapi id 15.20.4195.030; Tue, 8 Jun 2021 06:40:28 +0000 X-Gm-Message-State: AOAM532QylBFwgi5/aDcRb3xqnFMfTS8sbRqkvRdMdLvLcQMOwvIouY0 a+elT+DWu4ZBG0CpbFTGmPP27ALrmHdy/FHtzVc= X-Google-Smtp-Source: ABdhPJx0qzBzrVLoVm9n90u/hbWE+kSRjwsLV4ouR4icLpdk4XVfB3GHHiwvRKhfnQGP9fQdDbRbrjJgxdNC2/Bdza0= X-Received: by 2002:a05:620a:2942:: with SMTP id n2mr20058554qkp.412.1623134115928; Mon, 07 Jun 2021 23:35:15 -0700 (PDT) References: <7256195.zb9d8qvCYo@linux.local> <20210606184638.13650-1-wlooi@ucalgary.ca> <20210607083542.GP1955@kadam> <20210607084642.GQ1955@kadam> In-Reply-To: <20210607084642.GQ1955@kadam> From: Wenli Looi Date: Mon, 7 Jun 2021 23:35:04 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2] staging: rtl8723bs: Fix uninitialized variable To: Dan Carpenter Cc: Greg Kroah-Hartman , linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, "Fabio M. 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X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?dXNzMEwwcWNQT1pwSElMN2FqaVJ2NkZ5NVhUUHcyL3oxdUZDcGhRS1E3bTNE?= =?utf-8?B?NllHTC9yTFBqMVR3QXpsOFZYdnR2NE9ualJhTWVKa014Tml0MHFDZlhGcTho?= =?utf-8?B?aFQ3bjRYQ3d6TWR4U05MQURXK09VQjJBL2lSU1k4NTNIYVN1Q05nQlNOYjg4?= =?utf-8?B?OWlZWVZnVkpZcGl1TmlleGZSWGgvcWdDbDZWdHNXSmdsT3RBYmY4U1JjZ2VT?= =?utf-8?B?V3ViSUdxZFJIY3RLeFlLSEwzY2dPZlUxN3BpUzNaUk5WNm9KQUhGc2dPRTdP?= =?utf-8?B?bnlsVkg3ZERaaUtsK21tZmI3QkNDZVpmS3NHU2swTTVEUVljUEdNa0V3S0My?= =?utf-8?B?MUFSWW1pcVZDZ05jZVpqelhFSzNCNWJCMFZEQU1Ba2lIRmtCSXRPem8yQk1F?= =?utf-8?B?bG5LSm96bktoNms0eUpZcDdhVFA3M3p0S09jbit4NklGbFI3VDEvQ2srRkc0?= =?utf-8?B?NElFNDlScDhNamJ4RVNkVzlPMHJ5WlVyb0RBMVVRWjRjK29xb28vVnNqRjl5?= =?utf-8?B?Y05BOUY4bThPWTl2bE5DOUhVejBnakRHaG1BbVFsMGo1SFowa3kzWFNRd0Rz?= =?utf-8?B?RGpoeHNIRnhOTEROa3NvRWd0NGQwaVFmTnhGL2E4cnVtcmJRL1JWRjNZTFJR?= =?utf-8?B?L3FweTIrQlJleHVSL2F4Z1VJSEpVcG9UNVA2SDJnY1pDLzVmMTA2MXJRaU4r?= =?utf-8?B?MVdrN0lqaUljMU5LSGZQMjZYN0FNUUUrYmRmdFBEb3I4dHM2ZmlsK1pzQmVZ?= =?utf-8?B?THp0Z2lPLzlrc3FhVGxrcXFubG81bmRIUjg5VnQ4TG9ETDNSaDBRN2pPeW1i?= =?utf-8?B?cmZPUmMxMERiRm1rK1Y5bHN2bXRtdWVuNUE4R01aZUVhOXd6S3IzY2JFaFl3?= =?utf-8?B?dk9MOTUvNWpVS29mQ3A1Z1hGVXN0RHVXRWFjSkJ0NWlaUG5SMmFtWHhyQXNz?= =?utf-8?B?Tm4xeFU5S0EvM08wUjdrSUdLMkJOa0s1VlJsaTFIcUMvL0hXM1JQN3FESjFQ?= =?utf-8?B?Q3pPU0FwQ2RObjhhd0RKazVEQ1ZkSDhUU1M1d1BLcUZVeXQ2RXo5ejk2TUJY?= =?utf-8?B?dE5yUzI1VVdueGhPK2FKSHpxdzRFdjhGNW1HRmJIQ0g5L2lrSFJUYjgzdFVw?= =?utf-8?B?R3d4cnovbmM5N0twdWczV1g1TmZMeTFxWWFjNTJ1TzRnbkJzTk9ZWkhkR0hL?= =?utf-8?B?SkNWMUNWQ3F0SmVabmhRU242b1YzTGc1QVBUcUJZcHFuTlhUdnB3MWs3WFM1?= =?utf-8?B?ellDd2tuZmZoRXd5dk12OVZOT0pXSzcvL25xT1RySjdDVUx3RUJCRXE1ODl0?= =?utf-8?B?bDlaWStTTy9IMVIzTlNrWnNOMllIR0tJVDZPc056a3dQRERlMmI1dFpzbG8y?= =?utf-8?B?SWVReVVFbWJURzgwaEQrVHJYYUJZNkJNSGRxQUdVUnA1bS9tNXVkTmtXalk4?= =?utf-8?B?STdsalRLTnpURzhuSXNKYXJldEVwdFhwREZQTlk0Q0JDRFpsVzFCVGROOWQ2?= =?utf-8?B?cHpaZ2JROUJoemxsMGxtNkpJQzQ3R04wNm9ESG1abUM2RDFJeVVETm1CWEpX?= =?utf-8?B?Qy9NaEQ0RnRNeHRiSTVOTnFraVdZa2NmNHE2TWJRL2dKbzVEeDNHR1JyMWhJ?= =?utf-8?B?U3BwdDVQUUt4d3UzSDlKNWxkeXYvUW9iY2RGd2xCL0NiUzJXUTFpS3JkMjZF?= =?utf-8?B?bTlpd3pKc3lwcWIvTjBtMEFMaTVoZTF3eHA0UVl3bDJkYWxnNU5MQW9IMGND?= =?utf-8?Q?G4auRdjpjPTXs6a/4ArpjPPfIYZlOH8zUr0DbNs?= X-OriginatorOrg: ucalgary.ca X-MS-Exchange-CrossTenant-Network-Message-Id: 1b4eae0d-cc3c-466b-d074-08d92a484ddd X-MS-Exchange-CrossTenant-AuthSource: YQXPR01MB3302.CANPRD01.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Jun 2021 06:40:28.3639 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: c609a0ec-a5e3-4631-9686-192280bd9151 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: dkgovS9Kr0XPee26Cf8scDy+wiZHDMppTnZHQxZgMR2njcHikr1ZpeodW6P0LCIfKz1innNZta8rbpZyF4wDCA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: YQBPR0101MB4682 I will resend the first patch. Thanks for your insightful comments. I was wondering why every other driver seemed to be allocating "struct station_info" using kzalloc() On Mon, Jun 7, 2021 at 1:46 AM Dan Carpenter wro= te: > > [=E2=96=B3EXTERNAL] > > > > On Mon, Jun 07, 2021 at 11:35:42AM +0300, Dan Carpenter wrote: > > On Sun, Jun 06, 2021 at 11:46:38AM -0700, Wenli Looi wrote: > > > Uninitialized struct with invalid pointer causes BUG and prevents acc= ess > > > point from working. Access point works once I apply this patch. > > > > > > This problem seems to have been present from the time the driver was > > > added to staging. Most users probably do not use access point so they > > > will not encounter this bug. > > > > > > https://forum.armbian.com/topic/14727-wifi-ap-kernel-bug-in-kernel-54= 44/ > > > has more details. > > > > > > kzalloc() seems to be what other drivers are doing in the same situat= ion > > > of creating struct station_info and calling cfg80211_new_sta. In > > > particular, other drivers like ath6kl and mwifiex will silently retur= n > > > when kzalloc fails, so this seems like the right behavior. (mwifiex > > > returns -ENOMEM from the place kzalloc is called, but if you follow t= he > > > chain of calls, the return value is ultimately ignored) > > > > > > Links to same situation in other drivers: > > > https://github.com/torvalds/linux/blob/f5b6eb1e018203913dfefcf6fa9886= 49ad11ad6e/drivers/net/wireless/ath/ath6kl/main.c#L488 > > > https://github.com/torvalds/linux/blob/f5b6eb1e018203913dfefcf6fa9886= 49ad11ad6e/drivers/net/wireless/marvell/mwifiex/uap_event.c#L120 > > > > > > Signed-off-by: Wenli Looi > > > --- > > > > > > v1 -> v2: Switched from large stack variable to kzalloc > > > > > > Nah, v1 was better, it just needs an updated commit message. See my > > other email for more details. > > I read this again and I thought I should provide some more information. > > This sinfo struct used to be huge and that's why people used to allocate > it if kzalloc() but now it's only 224 bytes so it's okay to put it on > the stack. > > And the problem was never whether the variable was on the stack vs on > the heap so changing that wasn't part of the "a patch should do one > thing." If you want to change it to kzalloc you have to do that in a > separate patch (don't do that). > > And you were reading Greg's questions as saying the patch was wrong, but > actually they were just questions. > > regards, > dan carpenter > 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,MSGID_FROM_MTA_HEADER,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 327D9C47082 for ; Tue, 8 Jun 2021 06:35:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1065260C40 for ; Tue, 8 Jun 2021 06:35:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230280AbhFHGhP convert rfc822-to-8bit (ORCPT ); Tue, 8 Jun 2021 02:37:15 -0400 Received: from mail-eopbgr670074.outbound.protection.outlook.com ([40.107.67.74]:64224 "EHLO CAN01-TO1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229507AbhFHGhN (ORCPT ); Tue, 8 Jun 2021 02:37:13 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=hyzt+nbQe3K1JyIWl+b/8gF/hqgO7zNtpRk9FM8F+Oiq8aF/0NCZlyZ4zZZqSWCsZ7aGhe88+tKTwxL4HJkWRl9dtYhavEAhlJYYkjEbXrmJCnw5+dTFs/p1Waf98btUrBu/qv1x1dQohTr3PoszlVx/6Qo7UmPPUunino/xGqQBZsMhizkeFFaooDfQTX3QHtnk32vx4TN5MbQmk4BjgNBHYDfPtBMT0pvqFH/9HIHQpRAuTXSQETSlcVq7padUlTFs9r8MjjBSptvht1mcmheye9iCyb8cq670QjSNdxG6P0uU1Dfg4YlYVO29gyWJVMyMuLiMmWyfs8N9jfd6dw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=3E88rt/rcU8KJQzYrauX2KMCvgO32lij5xymqVMBYAU=; b=dPl5T/1b6ENH4wX7kUF0dID80y13NfHlcauB+ko1xAbC95FnJo9gFM3CataL7nLi8wXXCAxV51cErZjNCfxWzrUpAz9r1JiAjupYbR0VwSkqhPMzBqIxExdQ84NCxqU+pbinT37Xckt/181f1WggJ59s7Uw/kn8wavbYMSN7toV5FO5tkwT+x1Glgfi66m64RoaXlznn0KTnwXj3tAVz6BE/8EWmz1bS6gb10RAyfE2DhMjH/ShNXXfHQHVxSgpE81Xy2/sxs2Dde+V7g09z/FfIr1YMqdzqyw7A/YmC1BJLFzBMYu1peJ1OcGAsKRsIHLt5AwFBWjI3LHqWsUSnhg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=ucalgary.ca; dmarc=pass action=none header.from=ucalgary.ca; dkim=pass header.d=ucalgary.ca; arc=none Authentication-Results: vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; dmarc=none action=none header.from=ucalgary.ca; Received: from YQXPR01MB3302.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c00:4a::23) by YQXPR0101MB1893.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c00:16::23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4195.30; Tue, 8 Jun 2021 06:35:19 +0000 Received: from YQXPR01MB3302.CANPRD01.PROD.OUTLOOK.COM ([fe80::90eb:8466:4635:4b35]) by YQXPR01MB3302.CANPRD01.PROD.OUTLOOK.COM ([fe80::90eb:8466:4635:4b35%7]) with mapi id 15.20.4195.030; Tue, 8 Jun 2021 06:35:19 +0000 X-Gm-Message-State: AOAM531xWa7QT2iPUDXO8DGnCyMP251XkFBjmc5uVwfzQbk62ipaIcwD grKkOnSvha5sGoTHo+tAWmLMmgdNSQU5NieqH2U= X-Google-Smtp-Source: ABdhPJx0qzBzrVLoVm9n90u/hbWE+kSRjwsLV4ouR4icLpdk4XVfB3GHHiwvRKhfnQGP9fQdDbRbrjJgxdNC2/Bdza0= X-Received: by 2002:a05:620a:2942:: with SMTP id n2mr20058554qkp.412.1623134115928; Mon, 07 Jun 2021 23:35:15 -0700 (PDT) References: <7256195.zb9d8qvCYo@linux.local> <20210606184638.13650-1-wlooi@ucalgary.ca> <20210607083542.GP1955@kadam> <20210607084642.GQ1955@kadam> In-Reply-To: <20210607084642.GQ1955@kadam> From: Wenli Looi Date: Mon, 7 Jun 2021 23:35:04 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2] staging: rtl8723bs: Fix uninitialized variable To: Dan Carpenter Cc: Greg Kroah-Hartman , linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, "Fabio M. 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Thanks for your insightful comments. I was wondering why every other driver seemed to be allocating "struct station_info" using kzalloc() On Mon, Jun 7, 2021 at 1:46 AM Dan Carpenter wrote: > > [â–³EXTERNAL] > > > > On Mon, Jun 07, 2021 at 11:35:42AM +0300, Dan Carpenter wrote: > > On Sun, Jun 06, 2021 at 11:46:38AM -0700, Wenli Looi wrote: > > > Uninitialized struct with invalid pointer causes BUG and prevents access > > > point from working. Access point works once I apply this patch. > > > > > > This problem seems to have been present from the time the driver was > > > added to staging. Most users probably do not use access point so they > > > will not encounter this bug. > > > > > > https://forum.armbian.com/topic/14727-wifi-ap-kernel-bug-in-kernel-5444/ > > > has more details. > > > > > > kzalloc() seems to be what other drivers are doing in the same situation > > > of creating struct station_info and calling cfg80211_new_sta. In > > > particular, other drivers like ath6kl and mwifiex will silently return > > > when kzalloc fails, so this seems like the right behavior. (mwifiex > > > returns -ENOMEM from the place kzalloc is called, but if you follow the > > > chain of calls, the return value is ultimately ignored) > > > > > > Links to same situation in other drivers: > > > https://github.com/torvalds/linux/blob/f5b6eb1e018203913dfefcf6fa988649ad11ad6e/drivers/net/wireless/ath/ath6kl/main.c#L488 > > > https://github.com/torvalds/linux/blob/f5b6eb1e018203913dfefcf6fa988649ad11ad6e/drivers/net/wireless/marvell/mwifiex/uap_event.c#L120 > > > > > > Signed-off-by: Wenli Looi > > > --- > > > > > > v1 -> v2: Switched from large stack variable to kzalloc > > > > > > Nah, v1 was better, it just needs an updated commit message. See my > > other email for more details. > > I read this again and I thought I should provide some more information. > > This sinfo struct used to be huge and that's why people used to allocate > it if kzalloc() but now it's only 224 bytes so it's okay to put it on > the stack. > > And the problem was never whether the variable was on the stack vs on > the heap so changing that wasn't part of the "a patch should do one > thing." If you want to change it to kzalloc you have to do that in a > separate patch (don't do that). > > And you were reading Greg's questions as saying the patch was wrong, but > actually they were just questions. > > regards, > dan carpenter >