From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f48.google.com (mail-ot1-f48.google.com [209.85.210.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E22763FE1 for ; Thu, 9 Sep 2021 11:46:13 +0000 (UTC) Received: by mail-ot1-f48.google.com with SMTP id l16-20020a9d6a90000000b0053b71f7dc83so2076672otq.7 for ; Thu, 09 Sep 2021 04:46:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=scnpuQEkIxlsg5dECCNfy9fibrsqF7ou9Zg/wTCMvoU=; b=HocwwpvIksbWJirVOnxgkgytjZ7wOGw3bbBsvcTefpQe6yTb8YILKbo9qwPW2zKcia uAvzxBZRpgb629jFpVbEEOWJ+FyUmtFR/cF8wq6OSKdFbdT6dCilHyNssc6kHAtZhAlL rbotHx+W8bj0o/uX2Qoirf8mDSm4E4bTDGD/zbWkpH3FdbS/9e2mUxUET2Jp7p8LBeom c/Ph7Mxz1urJJNZGVjAztutFhA/8G6fuU4qfvO2MhrVThrZ+ABBVhpaMWc73QRzkcfcR hWMwVAzQL2HlpF8GkxmfcwWBaiauMOfQn7/q8GJ8gqrNC+IH9pZ+T6Y59KHvss1wqSYA SSdg== X-Google-DKIM-Signature: v=1; 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charset="UTF-8" On Thu, 9 Sept 2021 at 12:49, Marco Elver wrote: > All architectures at least double stack size when using one of the KASAN > software modes that rely on compiler instrumentation. > > Until now, warnings emitted by -Wframe-larger-than could easily be > ignored, as we would still get a working kernel. > > However, with the introduction of -Werror (CONFIG_WERROR=y), it makes > sense to at least double the -Wframe-larger-than threshold for > software-based KASAN modes to reflect the already increased stack sizes > when building a kernel with KASAN enabled. > > Link: https://lkml.kernel.org/r/YTbOs13waorzamZ6@Ryzen-9-3900X.localdomain > Signed-off-by: Marco Elver FWIW, there's still no consensus if this is what we want, and the discussion continues at: https://lkml.kernel.org/r/CANpmjNPBdx4b7bp=reNJPMzSNetdyrk+503_1LLoxNMYwUhSHg@mail.gmail.com > --- > lib/Kconfig.debug | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index ed4a31e34098..2055bbb6724a 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -345,6 +345,8 @@ endif # DEBUG_INFO > config FRAME_WARN > int "Warn for stack frames larger than" > range 0 8192 > + default 4096 if 64BIT && (KASAN_GENERIC || KASAN_SW_TAGS) > + default 2048 if !64BIT && (KASAN_GENERIC || KASAN_SW_TAGS) > default 2048 if GCC_PLUGIN_LATENT_ENTROPY > default 1536 if (!64BIT && PARISC) > default 1024 if (!64BIT && !PARISC) > -- > 2.33.0.153.gba50c8fa24-goog > 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 7614AC4167D for ; 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Thu, 09 Sep 2021 04:46:12 -0700 (PDT) MIME-Version: 1.0 References: <20210909104925.809674-1-elver@google.com> In-Reply-To: <20210909104925.809674-1-elver@google.com> From: Marco Elver Date: Thu, 9 Sep 2021 13:46:01 +0200 Message-ID: Subject: Re: [PATCH] kasan: double -Wframe-larger-than threshold if KASAN To: elver@google.com, Andrew Morton Cc: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Arnd Bergmann , Christoph Hellwig , Guenter Roeck , Nathan Chancellor , Nick Desaulniers , Aleksandr Nogikh , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Taras Madan , linux-mm@kvack.org, llvm@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 9 Sept 2021 at 12:49, Marco Elver wrote: > All architectures at least double stack size when using one of the KASAN > software modes that rely on compiler instrumentation. > > Until now, warnings emitted by -Wframe-larger-than could easily be > ignored, as we would still get a working kernel. > > However, with the introduction of -Werror (CONFIG_WERROR=y), it makes > sense to at least double the -Wframe-larger-than threshold for > software-based KASAN modes to reflect the already increased stack sizes > when building a kernel with KASAN enabled. > > Link: https://lkml.kernel.org/r/YTbOs13waorzamZ6@Ryzen-9-3900X.localdomain > Signed-off-by: Marco Elver FWIW, there's still no consensus if this is what we want, and the discussion continues at: https://lkml.kernel.org/r/CANpmjNPBdx4b7bp=reNJPMzSNetdyrk+503_1LLoxNMYwUhSHg@mail.gmail.com > --- > lib/Kconfig.debug | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index ed4a31e34098..2055bbb6724a 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -345,6 +345,8 @@ endif # DEBUG_INFO > config FRAME_WARN > int "Warn for stack frames larger than" > range 0 8192 > + default 4096 if 64BIT && (KASAN_GENERIC || KASAN_SW_TAGS) > + default 2048 if !64BIT && (KASAN_GENERIC || KASAN_SW_TAGS) > default 2048 if GCC_PLUGIN_LATENT_ENTROPY > default 1536 if (!64BIT && PARISC) > default 1024 if (!64BIT && !PARISC) > -- > 2.33.0.153.gba50c8fa24-goog >