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=-2.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 2FC6FC67839 for ; Mon, 10 Dec 2018 15:44:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2FB42081F for ; Mon, 10 Dec 2018 15:44:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=tycho-ws.20150623.gappssmtp.com header.i=@tycho-ws.20150623.gappssmtp.com header.b="U3tlMd4U" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E2FB42081F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=tycho.ws Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728232AbeLJPor (ORCPT ); Mon, 10 Dec 2018 10:44:47 -0500 Received: from mail-pg1-f195.google.com ([209.85.215.195]:33141 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728103AbeLJPoq (ORCPT ); Mon, 10 Dec 2018 10:44:46 -0500 Received: by mail-pg1-f195.google.com with SMTP id z11so5149058pgu.0 for ; Mon, 10 Dec 2018 07:44:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tycho-ws.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=kWJ7MPiP+23wXkLUZinQpSSCzi/C5Xl/C9xfmDNevy8=; b=U3tlMd4UHCc9IMoa6Hq/DfltjFRj4yByOZNZ+OvgiFNssSAQLYsNgfOADyNeHArsh2 GoQMP9ftEV95ThGqKJK81JHNQQEEWoJjfbqjRBgpTw/YlXaroMh1N35d+T/U9VJmW/jW fO0jK6k5gVcEGCeas3ZeeEvAKlciJQjg/Wa2/G3EUG73DxvOncDLHeHpj79nXxe4+k0J Xtb7ytNp2myIbSfjhLO/8/G90s7DEJzLwNSrE4KaiyomF8y8XOsINCrfaC0yKmLmqR0J YeKvwK/O+KNk2uRmAakwPjvn9cgp5BvUiNsujdWpxrLyGloKTiACn/YybBi/HmVkfd4R EoJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=kWJ7MPiP+23wXkLUZinQpSSCzi/C5Xl/C9xfmDNevy8=; b=pOxLDP6/Z90nQZSs73mX0liuYos+E3ZU3k2xyYdusbt0Ek8DOi5Pz+RMqBDLEAHhlk vBE0MqGSBnV/yTq9GiiPIPaJVn690mzGAncv8w5gcGGVRoZ7QsODywHp02OYRyHLYoBL Pc/SktWU4JNajjt4Asp+dMux5Rm5PTPfCMLwz34q//bEnlyd8cUTlIgsYS+cHRnCfoW3 /Pbr1bKKVSqBe5sKFDTDYfNl0y/iT+Gvg31E+/+C1ymyF/FXtG/cNCyvihQNe6RhI4yA /Xdb4rqWtHE3O5CdWEBgEI8QMpAUmD7lcBlKbPHvr5C+zycSt7kmPPmC0PP/ayosHJR2 XWZg== X-Gm-Message-State: AA+aEWYCtWvOZwIl3MGu2/v+zYU9keBCt5Ek0+Z2Eu4WqVmL4d3NZP1E 7bCHgCEiXjMaKyw+QUmJU1PCIQ== X-Google-Smtp-Source: AFSGD/W9RV4OFbIjsR0ZarmVTQ2J8MVx7082ZpfJcwg4S9IiccRUq9ew0BkxoDoHEXZcwW/DmnSKIQ== X-Received: by 2002:a63:bd1a:: with SMTP id a26mr11134140pgf.121.1544456685431; Mon, 10 Dec 2018 07:44:45 -0800 (PST) Received: from cisco ([128.107.241.164]) by smtp.gmail.com with ESMTPSA id 4sm26959309pfq.10.2018.12.10.07.44.43 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 10 Dec 2018 07:44:44 -0800 (PST) Date: Mon, 10 Dec 2018 08:44:42 -0700 From: Tycho Andersen To: Oleg Nesterov Cc: "Eric W. Biederman" , Linus Torvalds , Kees Cook , Thomas Gleixner , Linux List Kernel Mailing Subject: Re: siginfo pid not populated from ptrace? Message-ID: <20181210154442.GA19268@cisco> References: <87zhtthkuy.fsf@xmission.com> <87k1ktqoe5.fsf@xmission.com> <87r2euiuql.fsf@xmission.com> <20181206192059.GD10086@cisco> <87lg528io7.fsf@xmission.com> <20181210153717.GA7581@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181210153717.GA7581@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Oleg, On Mon, Dec 10, 2018 at 04:37:18PM +0100, Oleg Nesterov wrote: > On 12/06, Eric W. Biederman wrote: > > > > The challenge is that we could be delivering this to a zombie signal > > group leader. > > ... > > > Sigh it is probably time that I dig in and figure out how to avoid that > > case which we need to fix anyway because we can get the permission > > checks wrong for multi-threaded processes that call setuid and friends. > > this is another issue... I am sure we have already discussed this, but I > failed to find any link to the previous discussion. > > > Once that is sorted your small change will at least be safe. > > I don't think so, any sub-thread can dequeue SIGSTOP unless type == PIDTYPE_PID, > this has nothing to do with the problems connected to zombie leader, or I > misunderstood you. I think the conclusion about this bug is that we're just not going to fix it, Kees sent a patch to remove the check from the test: https://lore.kernel.org/lkml/20181206235038.GA18273@beast/T/#u So I will drop my patch. Cheers, Tycho