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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7AA2EC07E98 for ; Wed, 29 Nov 2023 01:22:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B6BBB6B036F; Tue, 28 Nov 2023 20:22:44 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B1B336B0370; Tue, 28 Nov 2023 20:22:44 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A0AAD6B0371; Tue, 28 Nov 2023 20:22:44 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 8F3986B036F for ; Tue, 28 Nov 2023 20:22:44 -0500 (EST) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 5CDE5160425 for ; Wed, 29 Nov 2023 01:22:44 +0000 (UTC) X-FDA: 81509242248.04.21EE764 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf24.hostedemail.com (Postfix) with ESMTP id 7C10B180015 for ; Wed, 29 Nov 2023 01:22:42 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=HTEloEWx; dmarc=none; spf=pass (imf24.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1701220962; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=tpFoDWxzhly8vBWsBuFUUlmjaSBQExvhtIJrmrRoKEE=; b=apMch3Wlc+tUllJuVisHhXt8DSVHieF+CpNKFNWbMqa0zjc/6rezElAwtrlnLe1clTPE2E WUGv9NV9OarS1gehmIWgcUn2kolNjU5oF8vcmKQCb0s7tJglbdK6OeMx5ZV7Rkf0FJiybN 7lEFE2oCxFW53UEibyUb5GIp8cedQXA= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=HTEloEWx; dmarc=none; spf=pass (imf24.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1701220962; a=rsa-sha256; cv=none; b=GuSUaZFzJHtnRDIjIYTjh2N9COkyPKC4aUFzABSxOhc+geHitZEoGJteqQpHQq3WVeFhU3 zyVrMJOgZG8My6baN8bhWd/WxmCkf42x6YdNHZq234xhbLBeFF7TDmU/4nbrQocf8WFW+o SKtmttTPm0JIhAfWScL5OtKM+jNu8JA= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by ams.source.kernel.org (Postfix) with ESMTP id 7B95FB835E0; Wed, 29 Nov 2023 01:22:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67609C433C8; Wed, 29 Nov 2023 01:22:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1701220959; bh=FBEAIzoLgu9Zkuu5c9UADybKG5tCWoq0pA1ohTQwa20=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=HTEloEWxitIAf4LrB+uGaCeVqy52QvkDsiW2ua5f4z/AKXmiI4hBsmwz7PT6WTZ1s Wxwfavqo2J72G1RZWH7aANFIO7lWJsNGHPpk1qGbaREMhcIco32+aA0fD6htjwWtLz m3FgVonjktFJ978Fuc/dQrQaVIQfLkN/ghI7VTIk= Date: Tue, 28 Nov 2023 17:22:38 -0800 From: Andrew Morton To: Haibo Li Cc: , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Matthias Brugger , AngeloGioacchino Del Regno , , , , , , kernel test robot Subject: Re: [PATCH] fix comparison of unsigned expression < 0 Message-Id: <20231128172238.f80ed8dd74ab2a13eba33091@linux-foundation.org> In-Reply-To: <20231128075532.110251-1-haibo.li@mediatek.com> References: <20231128075532.110251-1-haibo.li@mediatek.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: zfzz1mew73meo9k4p36y8mpx4kf98ydb X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 7C10B180015 X-HE-Tag: 1701220962-970334 X-HE-Meta: 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 FhfTdRB3 uf3DNl+gNCQk2Pdk76LrqOlCJ3hRjnvh2317CLa8IMBgBAf5FUyJ+YK2uGewtfMLm32PclVdfLaQ4URBRyTFO7iUyRwlJ3EL+DE78nfcb7pweCWPOJkUAwbT4BqnRZo1NfAAnbWkdPQBzoixC49Awnw/wgjnAlixDy19T+yA7uBu82DelTQq9uiLpqALEoCZe7Z9a8LOWzIgl9/E65zZsW4xzw7jYzNpItPhmH/vjc/HDOiWjKYAMW5x43X9pDD5n4yokSko+j7mip7Z6lM1iQzYs4UKUap3YQxsWkgRozzq+mJVOOXH4GIJa4dKgTZ7maLXilMcsdxwGFDdYv0iRYQhpdP7h1PqQgKkc 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: List-Subscribe: List-Unsubscribe: On Tue, 28 Nov 2023 15:55:32 +0800 Haibo Li wrote: > Kernel test robot reported: > > ''' > mm/kasan/report.c:637 kasan_non_canonical_hook() warn: > unsigned 'addr' is never less than zero. > ''' > The KASAN_SHADOW_OFFSET is 0 on loongarch64. > > To fix it,check the KASAN_SHADOW_OFFSET before do comparison. > > --- a/mm/kasan/report.c > +++ b/mm/kasan/report.c > @@ -634,10 +634,10 @@ void kasan_non_canonical_hook(unsigned long addr) > { > unsigned long orig_addr; > const char *bug_type; > - > +#if KASAN_SHADOW_OFFSET > 0 > if (addr < KASAN_SHADOW_OFFSET) > return; > - > +#endif We'd rather not add ugly ifdefs for a simple test like this. If we replace "<" with "<=", does it fix? I suspect that's wrong. But really, some hardwired comparison with an absolute address seems lazy. If KASAN_SHADOW_OFFSET is variable on a per-architecture basis then the expression which checks the validity of an arbitrary address should also be per-architecture.