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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B024AC47422 for ; Wed, 17 Jan 2024 09:50:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2CEE66B00CE; Wed, 17 Jan 2024 04:50:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 27F766B00D2; Wed, 17 Jan 2024 04:50:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0D1996B00D7; Wed, 17 Jan 2024 04:50:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id EA4F26B00CE for ; Wed, 17 Jan 2024 04:50:26 -0500 (EST) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id BFFBA40A4A for ; Wed, 17 Jan 2024 09:50:26 +0000 (UTC) X-FDA: 81688332852.26.D21ADA5 Received: from EUR03-DBA-obe.outbound.protection.outlook.com (mail-dbaeur03olkn2106.outbound.protection.outlook.com [40.92.58.106]) by imf14.hostedemail.com (Postfix) with ESMTP id EE2DF100004 for ; Wed, 17 Jan 2024 09:50:23 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=hotmail.de; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf14.hostedemail.com: domain of bernd.edlinger@hotmail.de designates 40.92.58.106 as permitted sender) smtp.mailfrom=bernd.edlinger@hotmail.de ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1705485024; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ngBKJQzTnGcPenI0VR4L67Dis8vzs27DKdd4wRD6qKA=; b=GAXsZ2+XE30f6jK9PHY2cSUPRxaSNoAXtapkiuwlRxVfZryFMaId9L/MdZwk2+zHpUIRyp DyGqQq6/AcBFsaZ4S9SzMmzTVG9erUM/McyGppTjatfQ4/I5ubIev9ItKoPbD+4skvNZ9K 5LaCmWQRSwNVu/hWeVCygJhWUp0MwQ0= ARC-Authentication-Results: i=2; imf14.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=hotmail.de; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf14.hostedemail.com: domain of bernd.edlinger@hotmail.de designates 40.92.58.106 as permitted sender) smtp.mailfrom=bernd.edlinger@hotmail.de ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1705485024; a=rsa-sha256; cv=pass; b=aGyBJTGf9dTFhQ7banPeOjilJz2wphFksHQxHlvvPmpi0Zd27zJtjPtM8IlRdjNuaZNkfH 3iLl4+wGGRolQlyNPb5S8+XtVuYMA3/WmUrvJVq2qEGupJ+Cd6ku5o5zlur9zNV62raC+W zKzJr256pjNBr4X9gcemGv8MHeJLxwU= ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=EuRchGId7vudaB70dHqTEMPAG1xAdVyV4Yo9jp4lOticKUuIYGidosfyMArDOGY6do9xlCKb0ujkqz0KNSQsqU7iPVVXl0N1V3R7xhXByXLt6zQK2SPuLwj45jHvtqC+KfQsOSeh2VLJbzjybua9/cRUJeNNi8u0NAbjQCF0T9dHrzJPMBWC7IdObnCdb4SLeYmQTsVvuDePnnTrfn6PRsHOvjPmQC5t3/08Xc98oKLCyCAaEVUEh1S1clFi51hqqgOtrEt8fUmQnAVoKlPNDCmMmujvBuFO29Q1j7k83p03PlCCx/kYwoReWwLDFas1huZnWn89/svefOj5rI4/hA== 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-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=ngBKJQzTnGcPenI0VR4L67Dis8vzs27DKdd4wRD6qKA=; b=fXtZvi+SB+RWf5DFsEjAXyyAS2PsV9paSXPrLfDf45APC9eKOv3xHp0ZyC+dNG2MUjJTTLPsxjCVjnaNeP2w6gNS7Z7tukY0At+u715lZlv7T9dygc/5bb87JzXQvAUS8K+lJ2xWX6KEaga/U51G8BH1EV9lGTF6fGVpQY27HFvs1TyZA+6Npl9faw5rnSEA7eXcDosp17J05TMb/v2HGQAnZbIKz7B9HI01jiDk6m0put+ehp9+Jvw4AQsUsmydZhzXgJZXqobvyXKSKlYLH6deUOW64v/pdmUHroyrirHFnSLpW14auD2PNkokiwkzzT64A4nyRtlg/Uq+A+8MSw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=none; dmarc=none; dkim=none; arc=none Received: from AS8P193MB1285.EURP193.PROD.OUTLOOK.COM (2603:10a6:20b:333::21) by PAXP193MB1582.EURP193.PROD.OUTLOOK.COM (2603:10a6:102:136::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7181.29; Wed, 17 Jan 2024 09:50:19 +0000 Received: from AS8P193MB1285.EURP193.PROD.OUTLOOK.COM ([fe80::897e:cfd5:b29b:c611]) by AS8P193MB1285.EURP193.PROD.OUTLOOK.COM ([fe80::897e:cfd5:b29b:c611%6]) with mapi id 15.20.7202.020; Wed, 17 Jan 2024 09:50:19 +0000 Message-ID: Date: Wed, 17 Jan 2024 10:51:14 +0100 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v14] exec: Fix dead-lock in de_thread with ptrace_attach To: Matthew Wilcox Cc: Alexander Viro , Alexey Dobriyan , Oleg Nesterov , Kees Cook , Andy Lutomirski , Will Drewry , Christian Brauner , Andrew Morton , Michal Hocko , Serge Hallyn , James Morris , Randy Dunlap , Suren Baghdasaryan , Yafang Shao , Helge Deller , "Eric W. Biederman" , Adrian Reber , Thomas Gleixner , Jens Axboe , Alexei Starovoitov , "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , linux-kselftest@vger.kernel.org, linux-mm@kvack.org, tiozhang , Luis Chamberlain , "Paulo Alcantara (SUSE)" , Sergey Senozhatsky , Frederic Weisbecker , YueHaibing , Paul Moore , Aleksa Sarai , Stefan Roesch , Chao Yu , xu xin , Jeff Layton , Jan Kara , David Hildenbrand , Dave Chinner , Shuah Khan , Zheng Yejian , Elena Reshetova , David Windsor , Mateusz Guzik , Ard Biesheuvel , "Joel Fernandes (Google)" , Hans Liljestrand References: Content-Language: en-US From: Bernd Edlinger In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TMN: [a1slPzDbHiej5yQ5B6H71L47/jDSwUtTwd4wZciRfoD6o7RsHe2CyRGURISCVsMZ] X-ClientProxiedBy: FR0P281CA0137.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:96::13) To AS8P193MB1285.EURP193.PROD.OUTLOOK.COM (2603:10a6:20b:333::21) X-Microsoft-Original-Message-ID: <1c6bc4f2-4e75-43e3-a77a-a08f15467cad@hotmail.de> MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: AS8P193MB1285:EE_|PAXP193MB1582:EE_ X-MS-Office365-Filtering-Correlation-Id: 88918171-dadd-4f09-1ae7-08dc1741b6c0 X-MS-Exchange-SLBlob-MailProps: AZnQBsB9XmqqMbmmUl3hmy+2IMtEJKZcwk92VJ/r+pDByb+73YMPZVlRtVvNLFeTdAw/oHz0yQoai782yWJyyyJkqbEN0QOaf4RiWYe0LH5Ib1JZtDWthECpdE50pBCEIoJTNmH584porW09MRopAb8DPbYIzExfX3SgQY3hBCilpZqiU88jy8d77Xa4LDX4P5VkHHGGSyihOYXCaA7hUItCH/101GG9oWg1YR8N66uKuOP6+do2KVnrgNSTqYd0cTUppvj1OH9IvmgMBYUuk5xIkd8xxHeiyl4qS5PzqUTXBCJkG9E4/8MJDAeVXHt0gaaKz0x2zXUt0OcK9BQrSRuTGuupl++nrKBYaeUZSME1zAKNOhwcJ+K/fP/anFnv8cvPfIdqh9x5/yAkZqCwyuk1mWIRWULbW4yZCEeAsxnHjntiCCpvvRo6O8vSZcW+U9z1/16Os2GAk48til74U2XA2N4nbOoq5z/0bMjo4+t8xnQwgCUNLxgyP9p6M1Nb9NPz1ZsYfKYpRgg8X0Vy2uLImFAd8TD8OrZ0cGEDSiZKkECZ/ehu4tiQPpB6CXHGATWAxDUP7tHtG7c7P+FuXZHEW+KoIAajKNSqpGtdkc8v7Pls6YPsaLEJbbS7ulcWDs5a3SsIunsbifDEVkkyo16ox8u29IxfOI6Cqu9QnK4wPxeNBnfZDjmZZzrF5z8dCdp0n+akQiK6zZDipXpM9i0A3lHt1WIUda0NZetPb29T7SMiHpphgQjcYXYmHn0Nfauv1dFIjuI= X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?WXE1UEVzeEZ1eDdEVk9obld3Uk5GUTNCVk5TaTN3NHdkMzZKMjNMVENZNllC?= =?utf-8?B?NVZtbTRTdE4zbUdScDYyZkJPelNEYjYxK1B6SS9kSlk3WWpWRWxiSjFBdE16?= =?utf-8?B?dmVmZWc3WWsyQmZDbjA5bjRQVWdtTy9mNEUzUnFZTDZzM0dJbHVreHE3ZlVa?= =?utf-8?B?T3FYTGRPaGxXdkhpQzlzWnBmNDE0VWFaRGNiWEN6WEtrSWdORGNFQUE1eUF1?= =?utf-8?B?ZlhuNVNGM05tOTdpSE9leWxPVm5aT1hFNHhzZ1d2V3dhbDJsU25TRzBab1JS?= =?utf-8?B?SEZReTBZNUIyaTRuM0hVUGFLSXFETEpWODZuMk9FY2dFVEVrQkdqTVdhUFpG?= =?utf-8?B?aVRxYUpDTGFsdzkwZlpxb3Q3R3BBVzVwWW9JNzhxQnAvZHRqcmFOelJFaUZC?= =?utf-8?B?YWp6MHAvc1VYRm9EZmx4UWQwUEg1eEp2WDN2N0dZWWRmRE5KbVhPaStxZldh?= =?utf-8?B?aTQzT2luTTlEY3hmSnF4aTdCUHpFeVUwbFJldC9GelhHd0EveWtSVHI2eWhX?= =?utf-8?B?NlozeFFYOXdSMHdtbC9kbll0c3RmeHp4ZCszT3RHdzRCMkRQVjNFbFdUTWk2?= =?utf-8?B?T3Fmc3VEb2tCZm80UjBDYVNRU1J5cUJkNjJSTlB5SnBGbTlXQ0RmaFV2Skt1?= =?utf-8?B?aDNSTzFFRHpQQmJkNlVaN0V3UEN0bjhyUmVvWFgvVzlwQ29paWhvWUZyRldv?= =?utf-8?B?cDNVaWQzOW92c1c3ZXV4VnhJdGR5YlliWHk3enlQSjlERVFIcnRCVWVtM3hF?= =?utf-8?B?Rk9rbWkwd1k4c3krclJUUHM3SE1XNFdLdjh6d3R5RFk5YSt5V01qUGNKZzI1?= =?utf-8?B?ZTdRMWZsbjBHcFJtUjhtcXd3ZGRaS2dYMVpEOHZyK0VWTk45L1BHTlFHMlVp?= =?utf-8?B?NHdpRXhPelN3VWFWYmprU0V6K3VsNENSWklhR0lmZ3p0SFE5MUdPRyt2cEs4?= =?utf-8?B?c1ZRRGpTSVRZWk1GdzVyT0NibEorNnNqR3NqN2tGRjNCOHpxWU5sRE54akIr?= =?utf-8?B?SUo5cjJaQXl6R3V2YjVLbmhCTnAwSC91Y2FnM0cwZ2prTGFNS2RtWVE3NFdK?= =?utf-8?B?S1dsRTFWeU81bHZ3WUYzWk0xNUhNZUFUWjhTS1QvT09mNFJIb2RQTk92TEp2?= =?utf-8?B?MlJhUnhMQjRidk1iOUF2Q3FVdnU2UFpob01CSURPNEJUcXBZSUhoRTZ5U2NJ?= =?utf-8?B?Z0RxOEJmMnhhZmtEQ3EybzRwUFBTYnN5NVJQQ1djL0VGbnk1c2h5aSszMWho?= =?utf-8?B?Y1hZT1MwNHNIR1N1MVpZaG5FdTlIby9MYkpkV3JXNElRSU9RMWlld1kxd0pO?= =?utf-8?B?WmxhNkM3cURyQWRNb25MaHFQS2F2TS9KNTI5c1N0bnNkZ2dQYVByUXluUElr?= =?utf-8?B?RXRhYldialpUYTgyZGlmQ0M3WWg2b2h0VjZ5ZllxVnp5b285ZXVzampWYUsw?= =?utf-8?B?emZEUHljYjloRGtBS1NtbnZUdEsrNitTL1R3MXovdEZPdkRhOTVvN2YxNWVT?= =?utf-8?B?cmRQRXBhRlhkcnMyL0trbEpkdzJSbGJPOUJORFAwTjRYTURjR3ZJVnpZN1ZP?= =?utf-8?B?c1k1ZzRXSzJNUE0zaTQ4NFJ4NjRhS2pVUmJkL3BZcW5kUEhYWkFLZUhNb0ho?= =?utf-8?B?V215cStmeVhHZUxDRWQ5Z0V1amV0NVdLTHlaenladmNrOFJYRlU5S3RXQk1P?= =?utf-8?B?WHcybjlzRWhRd1k3VURKT0xRM3JVM0NJRWd4VFZFd3pkYzkwenVWbVZJMjFr?= =?utf-8?Q?LBquwdGaRfJoIGjXAo=3D?= X-OriginatorOrg: sct-15-20-4755-11-msonline-outlook-80ceb.templateTenant X-MS-Exchange-CrossTenant-Network-Message-Id: 88918171-dadd-4f09-1ae7-08dc1741b6c0 X-MS-Exchange-CrossTenant-AuthSource: AS8P193MB1285.EURP193.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Jan 2024 09:50:19.0536 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-Transport-CrossTenantHeadersStamped: PAXP193MB1582 X-Rspamd-Queue-Id: EE2DF100004 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: hagxwh3hypxt1tp4zp7syqyfqhuxhebu X-HE-Tag: 1705485023-692715 X-HE-Meta: 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 0AsSe65v Et2S5BwPt+k3x5v5/wvHzsAGgyZqrM6jX+lV+OfnUbQCQW0QJtQYVSK72k7/wG3WKVV1LvzV+N/bEF8dSUS1gRSuCNBofaaHtnbmlR2QGqSZ6cFNAGTEyVrUpGmf5E63sHt3qSkXPUN8jNf557YeMXHGC5oH3SAPQjzk0ap1JeayyewG009nvlYtN7O1mVeZfxZTzV/XW4r6iWT+1S1iBent4HChC9oGDJKOSxuWkd0tzRo775t05eoE7QyDMLKYMU1Od2fpSERZfASKbGsj+dNx5dBq8e3AwZEu1XqxG5eq1nsBduyyE3YbIsOIv6DPuoEdm2zhaypFSmri8Or8hJpVZ+cVcWZH0UYcqn2x/zc/rEkotH68acAyWYqfs6NS/dkB7274CTwipQFlLHaiN25kst+w/eZJTnJcwuM8o+fgqrOCGNlWRijP4ow== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 1/15/24 20:37, Matthew Wilcox wrote: > On Mon, Jan 15, 2024 at 08:22:19PM +0100, Bernd Edlinger wrote: >> This introduces signal->exec_bprm, which is used to >> fix the case when at least one of the sibling threads >> is traced, and therefore the trace process may dead-lock >> in ptrace_attach, but de_thread will need to wait for the >> tracer to continue execution. > > Not entirely sure why I've been added to the cc; this doesn't seem > like it's even remotely within my realm of expertise. > Ah, okay, never mind. A couple new email addresses were found this time when I used ./scripts/get_maintainer.pl >> +++ b/include/linux/cred.h >> @@ -153,6 +153,7 @@ extern const struct cred *get_task_cred(struct task_struct *); >> extern struct cred *cred_alloc_blank(void); >> extern struct cred *prepare_creds(void); >> extern struct cred *prepare_exec_creds(void); >> +extern bool is_dumpability_changed(const struct cred *, const struct cred *); > > Using 'extern' for function declarations is deprecated. More > importantly, you have two arguments of the same type, and how do I know > which one is which if you don't name them? > >> +++ b/kernel/cred.c >> @@ -375,6 +375,28 @@ static bool cred_cap_issubset(const struct cred *set, const struct cred *subset) >> return false; >> } >> >> +/** >> + * is_dumpability_changed - Will changing creds from old to new >> + * affect the dumpability in commit_creds? >> + * >> + * Return: false - dumpability will not be changed in commit_creds. >> + * true - dumpability will be changed to non-dumpable. >> + * >> + * @old: The old credentials >> + * @new: The new credentials >> + */ > > Does kernel-doc really parse this correctly? Normal style would be: Apparently yes, but I think I only added those lines to silence some automatic checking bots. > > /** > * is_dumpability_changed - Will changing creds affect dumpability? > * @old: The old credentials. > * @new: The new credentials. > * > * If the @new credentials have no elevated privileges compared to the > * @old credentials, the task may remain dumpable. Otherwise we have > * to mark the task as undumpable to avoid information leaks from higher > * to lower privilege domains. > * > * Return: True if the task will become undumpable. > */ > Thanks a lot, that looks much better. I will use your suggestion as is, when I re-send the patch next time. >> @@ -508,6 +531,14 @@ static int ptrace_traceme(void) >> { >> int ret = -EPERM; >> >> + if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) >> + return -ERESTARTNOINTR; > > Do you really want this to be interruptible by a timer signal or a > window resize event? > I think that is kind of okay, as most of the existing users lock the mutex also interruptible, so I just wanted to follow those examples. Thanks Bernd.