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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 30C4BC43331 for ; Thu, 2 Apr 2020 02:06:36 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 7817A2072E for ; Thu, 2 Apr 2020 02:06:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="FEz92/cj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7817A2072E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-18366-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 5704 invoked by uid 550); 2 Apr 2020 02:06:29 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 5683 invoked from network); 2 Apr 2020 02:06:28 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=xQMUHcx5ZJebHuFeNsiV5oTqPrmJdOW/j745+2PrxT0=; b=FEz92/cjgu/KjeUfKUAamLHbiMYZP/JE8iQyr8PNIMC5adYQCca21soCJysmTW8le/ u+EmuDxNfwEIB6iFxacesqUbrDJuUXTQH1CifqeNvpd7zFcILB7eKw8/Qk1LJLcobXrc 6HoPfDxgcA61kzOR0e4ZTAsOnzIaIrzLDUVEs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=xQMUHcx5ZJebHuFeNsiV5oTqPrmJdOW/j745+2PrxT0=; b=WQowKhFzN4RJL92SrgT7Es7Nn59RdQ9H/UIYGa+E8U/UXxFGwpoka2p3XDPWj5XiBT /DwXoiLgBxkpsGchZGSfPO/E1x0sRSKyOyOMYbT8m/x2VZ7DwPNaFMJ2N4dodZNivDsk lINrLncTZ282FHNP8e0Z6wFBlmFWD0dxbB//kI5oEZfD2F8sLPbsXwLiFffyIUmT0oV8 6YKkJEPiVLBvNgsobOip0eB9t1VSkQ4Equ+f6GUoaSpW1USaWcCLwIlxmr6EDmP7oM5H KiFgk5E27fUylUXD5oUiVtJ+P8pA1SKfyP1fN+TC+vSoS8Ya6SNLEC8cli9OUSrIOml5 CpWA== X-Gm-Message-State: AGi0Pub7OtVeZeCoQytz9IWYiViJsz8gD+O4KfSSBEZ6ZjgUq/yUZ3aq VGxOUQwnRDw6DYVSQXqLwz0+9W9xmcI= X-Google-Smtp-Source: APiQypLuJzXALIoKw/Y13zWVlk8oZuUrIGt7exXdVoGLI+M2nt5e+dvE5Imaa3ckKwZUoqqfWhxSow== X-Received: by 2002:a2e:9789:: with SMTP id y9mr534831lji.207.1585793176843; Wed, 01 Apr 2020 19:06:16 -0700 (PDT) X-Received: by 2002:a19:7f96:: with SMTP id a144mr643180lfd.31.1585793175190; Wed, 01 Apr 2020 19:06:15 -0700 (PDT) MIME-Version: 1.0 References: <20200324215049.GA3710@pi3.com.pl> <202003291528.730A329@keescook> <87zhbvlyq7.fsf_-_@x220.int.ebiederm.org> In-Reply-To: From: Linus Torvalds Date: Wed, 1 Apr 2020 19:05:59 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] signal: Extend exec_id to 64bits To: Jann Horn Cc: "Eric W. Biederman" , Alan Stern , Andrea Parri , Will Deacon , Peter Zijlstra , Boqun Feng , Nicholas Piggin , David Howells , Jade Alglave , Luc Maranget , "Paul E. McKenney" , Akira Yokosawa , Daniel Lustig , Adam Zabrocki , kernel list , Kernel Hardening , Oleg Nesterov , Andy Lutomirski , Bernd Edlinger , Kees Cook , Andrew Morton , stable , Marco Elver , Dmitry Vyukov , kasan-dev Content-Type: text/plain; charset="UTF-8" On Wed, Apr 1, 2020 at 6:36 PM Jann Horn wrote: > > Since the read is already protected by the tasklist_lock, an > alternative might be to let the execve path also take that lock to > protect the sequence number update, No. tasklist_lock is aboue the hottest lock there is in all of the kernel. We're not doing stupid things for theoretical issues. Stop this crazy argument. A comment - sure. 64-bit atomics or very expensive locks? Not a chance. Linus