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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C0358C433EF for ; Thu, 30 Sep 2021 15:18:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FE2661881 for ; Thu, 30 Sep 2021 15:18:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245514AbhI3PUT (ORCPT ); Thu, 30 Sep 2021 11:20:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245495AbhI3PUT (ORCPT ); Thu, 30 Sep 2021 11:20:19 -0400 Received: from mail-pg1-x535.google.com (mail-pg1-x535.google.com [IPv6:2607:f8b0:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5882C06176A for ; Thu, 30 Sep 2021 08:18:36 -0700 (PDT) Received: by mail-pg1-x535.google.com with SMTP id k24so6579261pgh.8 for ; Thu, 30 Sep 2021 08:18:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Z/xgE/Y55JRJKfdAPlV0ukAj6bmYdIAVihPBePNuMEA=; b=Z2IgmXvUaFEXY7MoioDiKe6ZZXF3Bz9nLqLBxBra5B6yYSfjaV6O3KO7hSmCQCYZwn AJym7zohhwCmLwm3Ggn4jIJhrIwFaKsw7T0/Byaoj/Q4zb48yyrzljuLX9WGvrE8k0xl YrDcPGeqFNU/vPgzQWAb2nzuj9yniB4QbcaIc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=Z/xgE/Y55JRJKfdAPlV0ukAj6bmYdIAVihPBePNuMEA=; b=YY10TbuMuV/onlbhJg4U2dAt/g86N32hta5nKOfTXBOYQ0D8Jio6xyL20PKhJ6VhC2 fBGe26rJwW0OY6xkBTGuyLawF/52ocNrQP2lDQxvI4zwUnBJydtUwx3PwmP464J/crHt fdbbf5psjNybxcnKylLFcJcJ2kgMttIoV8HutuKpozHRxylUMkdJ0uwm/O/QyfVbENjW GIoNmvCrGTIACdpkqifYwQnNXM1RMjLUb+3csNwbGLB1qkJPKEcAQoaeE9FYcJ4PVO4W ScN/gRlPX87zEat9Ky7Wx5gGDK5CVNmuR7wpi2Txdn+xUnabn8CqwGzoHhKeupBKYKqB iGBw== X-Gm-Message-State: AOAM530cAw4TQ2cgsnDXvkcMsZYtH41AU1jIWWB+ESAL3g0zqkwJXXNs LXE2t0warHvtOglyo/rn/sAwuA== X-Google-Smtp-Source: ABdhPJx9xd/CgJ2K56cg1nMviMwyZqmS6824yDtPEv7b6XWoioc9YvVjIpGU29bL2HCgdp9tPKZPhw== X-Received: by 2002:a63:1a64:: with SMTP id a36mr5432550pgm.225.1633015116124; Thu, 30 Sep 2021 08:18:36 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id c22sm3022703pja.10.2021.09.30.08.18.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Sep 2021 08:18:35 -0700 (PDT) Date: Thu, 30 Sep 2021 08:18:34 -0700 From: Kees Cook To: Peter Zijlstra Cc: Josh Poimboeuf , kernel test robot , Vito Caputo , Jann Horn , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Andrew Morton , Christian Brauner , Anand K Mistry , "Kenta.Tada@sony.com" , Alexey Gladkov , Michael =?iso-8859-1?Q?Wei=DF?= , Michal Hocko , Helge Deller , Qi Zheng , "Tobin C. Harding" , Tycho Andersen , Thomas Gleixner , Borislav Petkov , "H. Peter Anvin" , Mark Rutland , Jens Axboe , Stefan Metzmacher , Lai Jiangshan , Andy Lutomirski , Dave Hansen , "Eric W. Biederman" , Ohhoon Kwon , Kalesh Singh , YiFei Zhu , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-hardening@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v2 0/6] wchan: Fix ORC support and leaky fallback Message-ID: <202109300817.36A8D1D0A@keescook> References: <20210929220218.691419-1-keescook@chromium.org> <20210930010157.mtn7pjyxkxokzmyh@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On Thu, Sep 30, 2021 at 10:40:11AM +0200, Peter Zijlstra wrote: > On Wed, Sep 29, 2021 at 06:01:57PM -0700, Josh Poimboeuf wrote: > > > - Should we use a similar sched wrapper for /proc/$pid/stack to make its > > raciness go away? > > Alternatively, can we make /stack go away? AFAICT the semantics of that > are far worse in that it wants the actual kernel stack of a task, > blocked or not, which is a total pain in the arse (not to mention a > giant infoleak and side-channel). > > > - At the risk of triggering a much larger patch set, I suspect > > get_wchan() can be made generic ;-) It's just a glorified wrapper > > around stack_trace_save_tsk(). > > Done that for you :-) Thanks! I wasn't sure the renaming was worth the churn, but the other cleanups make it much nicer. :) Do you want me to re-collect the resulting series, or do you have a tree already for -tip for this? -Kees -- Kees Cook