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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 497C3C433DB for ; Thu, 18 Mar 2021 18:51:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18DF064E90 for ; Thu, 18 Mar 2021 18:51:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230008AbhCRSuq (ORCPT ); Thu, 18 Mar 2021 14:50:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232326AbhCRSuO (ORCPT ); Thu, 18 Mar 2021 14:50:14 -0400 Received: from mail-lj1-x22d.google.com (mail-lj1-x22d.google.com [IPv6:2a00:1450:4864:20::22d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2DA33C061760 for ; Thu, 18 Mar 2021 11:50:14 -0700 (PDT) Received: by mail-lj1-x22d.google.com with SMTP id 16so8795635ljc.11 for ; Thu, 18 Mar 2021 11:50:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Fbc9sU+W6vKEWiVuzKDAzNw80eLikWEk6fODgolKFf4=; b=gV9qbJJbak0NwyikP8/6txEAmG7g7SLhIJX+Fba6IeRHX5IoxW3jDRmclVA8qlMsfU kBomGiglv5B7gIvKdwq5SGwJtUllfBgQLIHwNh/WVAb97ZqgqeJTyXusK0PW1Wj+fYOv rl0s1N7K+FNq2o56hIXTtivX0CxG7t7dEc5d97ivUIvX37ZqHrzNwlcrq9j4CB6QD5AZ FeHFP2afJV+FdE2b5evL+4dEfkVW7uNreiqLUlcby8ZsFQAMpnQJcSvrJu2jiTgww+aJ 381Y3D1oh2tZ8y5qgSnmZEVEwtk5rESCQTRFKxxhKk5x/kGAlFPIcPsl06+uQd4ls14G ZbQQ== 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=Fbc9sU+W6vKEWiVuzKDAzNw80eLikWEk6fODgolKFf4=; b=HiFc9car/73+Gg6FVgmM4rpZ/PsuqS2QJc8H4SGLRIEyuTYt79rICCZdda8NA93TBH rMIZtp6ABXhLHNS1sAzTQia3YCI8yHemKA2WZhOWfY+J38fuis3dK8kZyioO7ZAeKxOw DQ2O+hJa/6++KJxO70g9F65gwQbfKc/er+5pdK0UPw/qy7eClTuZmHTRu95mHYJQ0dty jwKUZyHZurjCTBPJ5t6KFS6kQEQ7ZRYH/tNMY7nT32aZE2IyKcb1DpDpZZNYN8m5vD5H nAHiRZfyR/tE075p4DLArJ3j0nj3tqG4SuQe4asg6yODOODvXSvHUdAKSvhrVtkhoNB2 Iprw== X-Gm-Message-State: AOAM530xctyzrWHAj9kgcwUDLIIJ4fhKSxRIAOCRPmBN+m5pgnYVnI5c fa6ETaHOkQui/xbtqolkTfy3ZFXWjQfICyG/olJTSw== X-Google-Smtp-Source: ABdhPJyac78CV6QxdSD/anwHq7ZKXrz96rfsGARqrb7ZO61dgR01Qx1cNIoMLgd8++IChAjKUBiov3LjVFDjuzYsR2s= X-Received: by 2002:a2e:b88b:: with SMTP id r11mr6028781ljp.495.1616093412369; Thu, 18 Mar 2021 11:50:12 -0700 (PDT) MIME-Version: 1.0 References: <20210318171111.706303-1-samitolvanen@google.com> <20210318171111.706303-6-samitolvanen@google.com> In-Reply-To: <20210318171111.706303-6-samitolvanen@google.com> From: Nick Desaulniers Date: Thu, 18 Mar 2021 11:50:00 -0700 Message-ID: Subject: Re: [PATCH v2 05/17] workqueue: use WARN_ON_FUNCTION_MISMATCH To: Sami Tolvanen Cc: Kees Cook , Nathan Chancellor , Masahiro Yamada , Will Deacon , Jessica Yu , Arnd Bergmann , Tejun Heo , "Paul E. McKenney" , Christoph Hellwig , bpf , linux-hardening@vger.kernel.org, linux-arch , Linux ARM , Linux Kbuild mailing list , PCI , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Mar 18, 2021 at 10:11 AM Sami Tolvanen wrote: > > With CONFIG_CFI_CLANG, a callback function passed to > __queue_delayed_work from a module points to a jump table entry > defined in the module instead of the one used in the core kernel, > which breaks function address equality in this check: > > WARN_ON_ONCE(timer->function != delayed_work_timer_fn); > > Use WARN_ON_FUNCTION_MISMATCH() instead to disable the warning > when CFI and modules are both enabled. Does __cficanonical help with such comparisons? Or would that be a very invasive change, if the concern was to try to keep these checks in place for CONFIG_CFI_CLANG? > > Signed-off-by: Sami Tolvanen > --- > kernel/workqueue.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 0d150da252e8..03fe07d2f39f 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -1630,7 +1630,7 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, > struct work_struct *work = &dwork->work; > > WARN_ON_ONCE(!wq); > - WARN_ON_ONCE(timer->function != delayed_work_timer_fn); > + WARN_ON_FUNCTION_MISMATCH(timer->function, delayed_work_timer_fn); > WARN_ON_ONCE(timer_pending(timer)); > WARN_ON_ONCE(!list_empty(&work->entry)); > > -- > 2.31.0.291.g576ba9dcdaf-goog > -- Thanks, ~Nick Desaulniers