Received: by 2002:a05:6a10:206:0:0:0:0 with SMTP id 6csp1572154pxj; Sat, 12 Jun 2021 12:49:14 -0700 (PDT) X-Google-Smtp-Source: ABdhPJx8bJWo46001otEPund7r1l02gZTYwNQGcNbazTwHLVxxOlnv1JBRSeKY1WPER8nt8fMQzW X-Received: by 2002:aa7:d413:: with SMTP id z19mr9877242edq.37.1623527354640; Sat, 12 Jun 2021 12:49:14 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1623527354; cv=none; d=google.com; s=arc-20160816; b=iQ2hakktJ0pBEuPLcRh5uEaQR6nXbWVMtDnzEL0BdLsJBOuiz5DwD0MWpdoeZT7JE1 p4z6DcbY93szXUjfP+WGe+Xim61XT+38yE2RGdpl6oxqX/4ULxy37GQT7NvtV1c5QxBQ E7YV9JtN513r+PV54qvD4kmgdV5DW+z73EbhOdD3pVCqxhkVhPGUMGgGr/dJTu3KI2DB O6mU+3eMjKpac+LjEcthtFM61J4Ooct2vwqyqA7v5YR6iEhLWZ7pkVZEcK9KNS8UtakP 2cjPWRAorxepuPuGe1932AENXmSnvSlJ7eqJFNbeRValjB01/0D+0uVXlc3/By7/Zehr FNYQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:subject:mime-version:user-agent:message-id :in-reply-to:date:references:cc:to:from; bh=7OGnDu2el7h44QNdb63JFzI+rqnDKuqwe6FpFL+nwMM=; b=pW14hKrwMnzAzKuTBi8C7lhp0Ha+9GRS0tgNneZACN1vmZInQ5j/NvW9aIwV4rdCpp E+dyQ/LE0LjYW5JPeaoOVPBp5hsx7zg9pkxYNyts6RJv9WEeM/FhScPwJuI5cZOk+Ubi BtIO0juTTvspIf5e1zOADKqe1pXHwFFdm4I7me3257X9j6Fn/jRMZlDnuULfbje2U63O SdrqNolT/X3QOzbddQhSCkHLbkhHIJSZw1Ww5mORJlD855KYF7kfL41VUg1eR0UPZybr Zseu88o1k4KC/j0ArF2UN+56IUM5IqKxLN9opfFn5G6lcT2W9turfaX6g8lK/lcq3MW2 IbEw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=xmission.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id 7si8200460ejg.355.2021.06.12.12.48.50; Sat, 12 Jun 2021 12:49:14 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=xmission.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230186AbhFLTtu (ORCPT + 99 others); Sat, 12 Jun 2021 15:49:50 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:58004 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229753AbhFLTts (ORCPT ); Sat, 12 Jun 2021 15:49:48 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1ls9bd-00B7yK-Dq; Sat, 12 Jun 2021 13:47:45 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=email.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1ls9ba-00839m-4V; Sat, 12 Jun 2021 13:47:44 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Andrew Morton Cc: Bernd Edlinger , Alexander Viro , Alexey Dobriyan , Oleg Nesterov , Kees Cook , Andy Lutomirski , Will Drewry , Shuah Khan , Christian Brauner , Michal Hocko , Serge Hallyn , James Morris , Charles Haithcock , Suren Baghdasaryan , Yafang Shao , Helge Deller , YiFei Zhu , Adrian Reber , Thomas Gleixner , Jens Axboe , "linux-fsdevel\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" , linux-kselftest@vger.kernel.org References: <20210610143642.e4535dbdc0db0b1bd3ee5367@linux-foundation.org> Date: Sat, 12 Jun 2021 14:44:05 -0500 In-Reply-To: <20210610143642.e4535dbdc0db0b1bd3ee5367@linux-foundation.org> (Andrew Morton's message of "Thu, 10 Jun 2021 14:36:42 -0700") Message-ID: <87eed6zx4q.fsf@disp2133> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1ls9ba-00839m-4V;;;mid=<87eed6zx4q.fsf@disp2133>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+Lb/nnF3A2u0YB7jYNPcnJEbfzC5VPB3M= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on sa07.xmission.com X-Spam-Level: X-Spam-Status: No, score=0.5 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,T_TM2_M_HEADER_IN_MSG,T_TooManySym_01,XMSubLong autolearn=disabled version=3.4.2 X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.5000] * 0.7 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa07 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: XMission; sa07 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Andrew Morton X-Spam-Relay-Country: X-Spam-Timing: total 2478 ms - load_scoreonly_sql: 0.07 (0.0%), signal_user_changed: 11 (0.5%), b_tie_ro: 10 (0.4%), parse: 1.04 (0.0%), extract_message_metadata: 20 (0.8%), get_uri_detail_list: 1.00 (0.0%), tests_pri_-1000: 18 (0.7%), tests_pri_-950: 1.29 (0.1%), tests_pri_-900: 1.11 (0.0%), tests_pri_-90: 2229 (89.9%), check_bayes: 2217 (89.5%), b_tokenize: 7 (0.3%), b_tok_get_all: 6 (0.3%), b_comp_prob: 2.2 (0.1%), b_tok_touch_all: 2197 (88.7%), b_finish: 1.18 (0.0%), tests_pri_0: 181 (7.3%), check_dkim_signature: 0.54 (0.0%), check_dkim_adsp: 3.0 (0.1%), poll_dns_idle: 1.15 (0.0%), tests_pri_10: 3.0 (0.1%), tests_pri_500: 9 (0.4%), rewrite_mail: 0.00 (0.0%) Subject: Re: [PATCHv8] exec: Fix dead-lock in de_thread with ptrace_attach X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton writes: > On Thu, 10 Jun 2021 09:31:42 +0200 Bernd Edlinger wrote: > >> This introduces signal->unsafe_execve_in_progress, >> 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. > > Deadlocks are serious. Is this exploitable by unprivileged userspace? The processes are killable so I don't think this is the serious in the way you mean. In fact Linus has already said that it is not a deadlock. Eric