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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 74DA0C433DB for ; Thu, 25 Feb 2021 08:54:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 294C664EF5 for ; Thu, 25 Feb 2021 08:54:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235256AbhBYIyj (ORCPT ); Thu, 25 Feb 2021 03:54:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:42088 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236039AbhBYIyd (ORCPT ); Thu, 25 Feb 2021 03:54:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E839864EF5 for ; Thu, 25 Feb 2021 08:53:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614243233; bh=3fskHFgSnva8Oq9mRm63RNdT+l9AG26PccKquWMEDdg=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=P0WxhwO0ynipw7G8ePCXk6EUzIMeNTJfvQy9cOHNKqrnnPnMMDfLTdh7WOi3RXBLc qg97DnGmWdvv+/ZVuPdFwFyltbXWUTU1tSsFMnSE43HdOQsQjh8MBaeiqwA27QZ5ga Ld54IR+fqNoRAcw6g0SufJ2R/RROpYHuAvptVomRUDB6Mp4c5pii2ouG6YB8Jm3dCT GWY9ajI983pBKg2OO/ubKPyPTEIQ9yALi8LvCv3Gx1zp+Jgtu3q9ZNEqfA7ecYOGh6 PBkeTUNNqvdoIoxX4ngl5dYOR1EjLs9GlJ6OMnkbUMCbAisNAyoZ/pO8ERhgsDKLsC aRC7zvMAhK06g== Received: by mail-oi1-f182.google.com with SMTP id 18so5372432oiz.7 for ; Thu, 25 Feb 2021 00:53:52 -0800 (PST) X-Gm-Message-State: AOAM533S0R+htmbLDV6/K55J+gw2qpKWBuqbnhPwVGnNC/+l/J9HNS4n IOMadAkBq5C2UJO39iIDwhy13Zz+VL2MP7lJrPA= X-Google-Smtp-Source: ABdhPJxWZh7Aw0H3nKOaeXdp6UrihvNG+kAxuGiPufkd+9VN0+GWQpdrJHL1MLhBTcVpvzOpkIHoljBMPmpgAg2VanM= X-Received: by 2002:aca:4a47:: with SMTP id x68mr1177983oia.67.1614243232085; Thu, 25 Feb 2021 00:53:52 -0800 (PST) MIME-Version: 1.0 References: <20210224115824.1e289a6895087f10c41dd8d6@linux-foundation.org> In-Reply-To: From: Arnd Bergmann Date: Thu, 25 Feb 2021 09:53:36 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: incoming To: Linus Torvalds Cc: Andrew Morton , Walter Wu , Dmitry Vyukov , Nathan Chancellor , Arnd Bergmann , Andrey Konovalov , Linux-MM , mm-commits@vger.kernel.org, Andrey Ryabinin , Alexander Potapenko Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org On Wed, Feb 24, 2021 at 10:37 PM Linus Torvalds wrote: > > On Wed, Feb 24, 2021 at 1:30 PM Linus Torvalds > wrote: > > > > Hmm. I haven't bisected things yet, but I suspect it's something with > > the KASAN patches. With this all applied, I get: > > > > lib/crypto/curve25519-hacl64.c: In function =E2=80=98ladder_cmult.con= stprop=E2=80=99: > > lib/crypto/curve25519-hacl64.c:601:1: warning: the frame size of > > 2288 bytes is larger than 2048 bytes [-Wframe-larger-than=3D] > > > > and > > > > lib/bitfield_kunit.c: In function =E2=80=98test_bitfields_constants= =E2=80=99: > > lib/bitfield_kunit.c:93:1: warning: the frame size of 11200 bytes is > > larger than 2048 bytes [-Wframe-larger-than=3D] > > > > which is obviously not really acceptable. A 11kB stack frame _will_ > > cause issues. > > A quick bisect shoes that this was introduced by "[patch 101/173] > kasan: remove redundant config option". > > I didn't check what part of that patch screws up, but it's definitely > doing something bad. I'm not sure why that patch surfaced the bug, but it's worth pointing out that the underlying problem is asan-stack in combination with the structleak plugin. This will happen for every user of kunit. I sent a series[1] out earlier this year to turn off the structleak plugin as an alternative workaround, but need to follow up on the remaining patches. Someone suggested adding a more generic way to turn off the plugin for a file instead of open-coding the CLFAGS_REMOVE_*.o Makefile bit, which would help. I am also still hoping that someone can come up with a way to make kunit work better with the structleak plugin, as there shouldn't be a fundamental reason why it can't work, just that it the code pattern triggers a particularly bad case in the compiler. Arnd [1] https://lore.kernel.org/lkml/20210125124533.101339-1-arnd@kernel.org/