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 1C5DAC4167B for ; Wed, 29 Nov 2023 03:02:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6D0AA6B0388; Tue, 28 Nov 2023 22:02:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 659666B0389; Tue, 28 Nov 2023 22:02:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4D4CA6B038A; Tue, 28 Nov 2023 22:02:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 3446C6B0388 for ; Tue, 28 Nov 2023 22:02:02 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 0A6F41A0409 for ; Wed, 29 Nov 2023 03:02:02 +0000 (UTC) X-FDA: 81509492484.24.7F73A73 Received: from mail-pj1-f49.google.com (mail-pj1-f49.google.com [209.85.216.49]) by imf30.hostedemail.com (Postfix) with ESMTP id 469CA80010 for ; Wed, 29 Nov 2023 03:01:59 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="W4km/Vj5"; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf30.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.216.49 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1701226920; a=rsa-sha256; cv=none; b=BHEX1UZW4t79fHmgRCbiUtvMVkjfSJBNqVPXRzSBxBcjC26dcLj39baj46U6b4iSgstqtF KNKv1CQrjW0zvnkVPd6MRORtRCcLcHXQUxy7B9NkQEvtnu1yb9Plmkg+r0LgHXpFy8c0T0 yiMa6LIXJrPhX2ZbWd/oFXtbL0MnKw8= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="W4km/Vj5"; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf30.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.216.49 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1701226920; 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=YmmZdnMG5cx1ucOkJTYJz9C0ueulBI91QAmZKkzSQnk=; b=UUEufZJbSxS01zt2sClwuIK4eudlO+P8YUl0K+zI6TwjMnTXazgb1Zj9mtHoA/uVfhJwrZ ybVqPoMvHZDbXM7JhrH0w1AreSuPmjHcpjW9NBAIW2NnzWJ9pUpCpyeUffoUTZr49Pnpov WPmLEYgX7rJyVVnAah0bTxNnkKjEVwM= Received: by mail-pj1-f49.google.com with SMTP id 98e67ed59e1d1-285c3512f37so2986682a91.3 for ; Tue, 28 Nov 2023 19:01:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701226919; x=1701831719; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=YmmZdnMG5cx1ucOkJTYJz9C0ueulBI91QAmZKkzSQnk=; b=W4km/Vj5MhKnqHwhuSMMkOCZ9Xz13zn2yPZsbqD2cZlspN21ADOfSkPb0Rpnvs8NCx uWrkhkEU1uTT/jUORhgmUopZSbs+cNy5tG038odMqn+eC4WaGM2BqBGcROTXhM11f/pV 6Osbx5GkFkrmB6DaKGH2Yj0Y/iEnh7kicOfZxJXAQT0cvmp5oIMAJiwSyjsZ3XLOP8Us Dv/4cdTYC0syo0620zeBFeUTmzdudzLXi0jfTmnCT5dOnf7jvzPcvOvYPfY7Jwghlwh4 z4Iawgn6abaNFomp2Dw2Jru5plUhGcFBJZua9MMibFCjSj+9+DotVdT+DbnDqCF7kV1+ 8PtA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701226919; x=1701831719; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=YmmZdnMG5cx1ucOkJTYJz9C0ueulBI91QAmZKkzSQnk=; b=jTB2nihxKZ2iOmCOorgeDc8XMh3/pBEYuilKCkhfGOdmJ5iRNO43htDWYaTRyzu/lO nXkuPRAP0W5IbUK+he39t/WXcYav/DZ2JCTt3/8o2BqsEXaobtvBD0Xsu3p6xcT72aKy rGDXC10hxULI9+Q+nGwhv8BnorLjVx1A0q52Q1bYcoXfOyZodGxb+TfCWwOqJDhOS1+d WpvtMB2zaPeXB2H3gkoSk6IPxmcj0Q3kl3wIKalEeIIicCXrP0RJloIyk6ze/n9DY1+c 3a+rWdPokhyml8hCKIBEpWk522T6fenFxxnz5Ef+wsWOknSig93rFG/orQiKLSB+To9f emZA== X-Gm-Message-State: AOJu0Yx/blmdmqVnjWjNIDjh2Ph+ZiFKdp/jlDEXSeluH5VripngDH24 u0PSvEY4Fss+9DhjBE4IsK/IUxEVI8iixTjdnUM= X-Google-Smtp-Source: AGHT+IGnzMPnHxO60vC1ojrSQZx1ZUStF+SQpvY4lfHFS3JYWC+jAHzm4FZ5/2GQ51SFSCY35ZknJWpTMhCgJeAVM+k= X-Received: by 2002:a17:90b:4c02:b0:285:dbbe:1178 with SMTP id na2-20020a17090b4c0200b00285dbbe1178mr7726571pjb.39.1701226918871; Tue, 28 Nov 2023 19:01:58 -0800 (PST) MIME-Version: 1.0 References: <20231128075532.110251-1-haibo.li@mediatek.com> <20231128172238.f80ed8dd74ab2a13eba33091@linux-foundation.org> In-Reply-To: <20231128172238.f80ed8dd74ab2a13eba33091@linux-foundation.org> From: Andrey Konovalov Date: Wed, 29 Nov 2023 04:01:47 +0100 Message-ID: Subject: Re: [PATCH] fix comparison of unsigned expression < 0 To: Andrew Morton , kernel test robot , Haibo Li Cc: linux-kernel@vger.kernel.org, Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Vincenzo Frascino , Matthias Brugger , AngeloGioacchino Del Regno , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, xiaoming.yu@mediatek.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 469CA80010 X-Stat-Signature: bqxjkkxwhe1zadx59h6xbtd85frn1q3a X-HE-Tag: 1701226919-925481 X-HE-Meta: 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 HqrtIyuh 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 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 Wed, Nov 29, 2023 at 2:22=E2=80=AFAM Andrew Morton wrote: > > 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 "<=3D", does it fix? I suspect that's wrong. Changing the comparison into "<=3D" would be wrong. But I actually don't think we need to fix anything here. This issue looks quite close to a similar comparison with 0 issue Linus shared his opinion on here: https://lore.kernel.org/all/Pine.LNX.4.58.0411230958260.20993@ppc970.osdl.o= rg/ I don't know if the common consensus with the regard to issues like that changed since then. But if not, perhaps we can treat this kernel test robot report as a false positive. Thanks!