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=-7.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,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 8A33AC432BE for ; Thu, 12 Aug 2021 13:02:35 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0BC0060C40 for ; Thu, 12 Aug 2021 13:02:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 0BC0060C40 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 864A88D0002; Thu, 12 Aug 2021 09:02:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 815208D0003; Thu, 12 Aug 2021 09:02:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 616888D0002; Thu, 12 Aug 2021 09:02:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0098.hostedemail.com [216.40.44.98]) by kanga.kvack.org (Postfix) with ESMTP id 3BE068D0002 for ; Thu, 12 Aug 2021 09:02:33 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id BD5C7184188B3 for ; Thu, 12 Aug 2021 13:02:32 +0000 (UTC) X-FDA: 78466442544.15.C71C1D2 Received: from mail-ej1-f52.google.com (mail-ej1-f52.google.com [209.85.218.52]) by imf21.hostedemail.com (Postfix) with ESMTP id 7D155D012DD2 for ; Thu, 12 Aug 2021 13:02:32 +0000 (UTC) Received: by mail-ej1-f52.google.com with SMTP id gs8so11356035ejc.13 for ; Thu, 12 Aug 2021 06:02:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=A7pHKxayGFMZlOwIq/bHkeKVOMFNUJ88V3SLok4nSRM=; b=AyScEMSOxALQVA7V7H0KBjnoYK1AjzL1m1zPaNebYAx4mp4BLFUEGi5Njdc30IszK3 4CZ8q2CP66DEHbi3lNMPHseEX5gETKpNv/vpphK8qK4GyIz07y14K/lc1XyQv9jg+3Pi xK4cS82KOtsHAdQ0A4B67bBFW8tAM10e7fVDRIT1Kd8b6X1XuQNTDWg4+u6H9/9sfreC MF3VCCarR9k7QmUk/jjXymaQuiR1mn9nN2W6kMBM9Kjyly+qB6UBkNMU7Al1WxGhLD6w XPcwPmQOSZgEpLiy4DNcHxluKtXo1cAtFkWz7TQBfacaQ93Q/llEihP7PxraRhFZjeY1 t1WQ== 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=A7pHKxayGFMZlOwIq/bHkeKVOMFNUJ88V3SLok4nSRM=; b=HBgZzIors1++/10bIhfeotTMQgLulz+Pp/1VlfKym00QeFGnU/wJpVb55xuuEYIR2L AatGrxyR5LHZvFVtOLI4Rc5pyX7SUTmVzJQxEr7XZ0UggRc7+CSLy6D9n5xNxooNxOLj b4vtxBeov2gN9MfU/mSNF1S9Cscr0rE2nIO9P+agtGpZnFiyCF/t5NbTGvlnee+O00WU FGlgOLuU3XgJLF/RXvzlkj8Dy0c0AOlxpXB8617TPjazsjfRPrJBxa877Nju4kRSIkWf Dh/nGB9Ak8oG9iBU+zvV7AfizM1NVbL8edl/w71QipaqAQjODX91mQfiwZpNn+LQn0fE cD8w== X-Gm-Message-State: AOAM53128bp/nBc12NkN/7dk/GO4MWXEEJuzHWqEgn6/7cHEddE4ivHd XZgs5O94Ex/7AhtE6mb71btipqjGC5hq/1Hi02I= X-Google-Smtp-Source: ABdhPJw3NPmerm1ZyyZkYaCjvjDhCk6Sy/iLaJPCoxxlPk0pqhzjVJJ7SFB1aOFUKhcgIGH20Q+OxQQG5FQrS7BcSRM= X-Received: by 2002:a17:906:53d3:: with SMTP id p19mr3522667ejo.509.1628773351053; Thu, 12 Aug 2021 06:02:31 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Andrey Konovalov Date: Thu, 12 Aug 2021 15:02:20 +0200 Message-ID: Subject: Re: [PATCH 2/8] kasan: test: avoid writing invalid memory To: Marco Elver Cc: andrey.konovalov@linux.dev, Andrew Morton , Andrey Ryabinin , Dmitry Vyukov , Alexander Potapenko , kasan-dev , Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 7D155D012DD2 Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=AyScEMSO; spf=pass (imf21.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.218.52 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspamd-Server: rspam01 X-Stat-Signature: x9mcugyttzy6jb5n4exafdknzjcqm5dq X-HE-Tag: 1628773352-224570 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 12, 2021 at 10:57 AM Marco Elver wrote: > > On Wed, 11 Aug 2021 at 21:21, wrote: > > From: Andrey Konovalov > > > > Multiple KASAN tests do writes past the allocated objects or writes to > > freed memory. Turn these writes into reads to avoid corrupting memory. > > Otherwise, these tests might lead to crashes with the HW_TAGS mode, as it > > neither uses quarantine nor redzones. > > > > Signed-off-by: Andrey Konovalov > > Reviewed-by: Marco Elver > > although if you need a write primitive somewhere that doesn't corrupt > memory, you could use atomic_add() or atomic_or() of 0. Although > technically that's a read-modify-write. Interesting idea. I'd say let's keep the volatile reads for now, and change them if we encounter any problem with those. > For generic mode one issue is > that these are explicitly instrumented and not through the compiler, > which is only a problem if you're testing the compiler emits the right > instrumentation. On a related point, it seems we have no KASAN tests to check atomic operations. Filed https://bugzilla.kernel.org/show_bug.cgi?id=214055 for this. Thanks!