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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2109BC00140 for ; Wed, 24 Aug 2022 03:52:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234454AbiHXDwu (ORCPT ); Tue, 23 Aug 2022 23:52:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234403AbiHXDwm (ORCPT ); Tue, 23 Aug 2022 23:52:42 -0400 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8208491F0 for ; Tue, 23 Aug 2022 20:52:41 -0700 (PDT) Received: by mail-pf1-x42b.google.com with SMTP id y127so12344003pfy.5 for ; Tue, 23 Aug 2022 20:52:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc; bh=1mJLK6hvchjehsHzEl3FcCuJd52Ags4MhBAkvBSrkO8=; b=V+BeboyB52pIWv5vpduP3TvkOHnga0om6vi5F3s495lrnJuoBjUVULAGmQLyDwLdDl GTRSmL4+VnRRqPfjqE11cqxzklZWYfwlDrsZt8GpPWrQrEA3TJQL/cfT6BxaSjjQDCVW NYXeP6Ak4AEYA0dliJ8FAFzCZcWBGNgHKeRzmqN9SyoOFdkIqbO/+eb4nfzskJo2IyXG L4ORtgiC81jxctyH9LqJtHRPkfDKgRrluePFneMaqI4pyvy1BuQKNPdrvDKevcBpKAHX 4bFM0A0+Ko3WZKDZNLTG0f3PgIdvmFtsgNxxtBBSMdffNoNXY4/Q8e54zCjmN6nPfKcK YDMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc; bh=1mJLK6hvchjehsHzEl3FcCuJd52Ags4MhBAkvBSrkO8=; b=rtd65GZc9f1kpS4sQnEMHcxhVcCiydz39Bf4R+AnG0OecrMM8iOTvNVF8Q2uuHRQ9/ ETnhjl9MwdAVH7HZhOuKk6txJq395ZUzk1LkM+uWe2W9Ya1uvxRGu9tvjtA+JOxn1aBu fPBr9yJxSLUPBfU5tsVoEswhmX7vnD+Dj5mETxRCfVPfjnZfVcaaVrvJhLuvVXzmTJqb qeh6vGqxGYtB2pSwBN1RfApQ4cNZV88SwAIHhMKdhj5N0yk6YJyfx4+lU0Q9+R0z5jfK DOGg6B4S5sGkLDzZtKzVUIAm9MGVNLDmTgg0REmkFHn5gwu+U5tgHpwy/6HzurarunQz HoFg== X-Gm-Message-State: ACgBeo3EdenYUvbmTWQAAzlBhy/y3vSOd0WkKe7j3rJCR3GSeW5AhMVC kXatQJv5hRl4RgegaAC86QRtHQcgcz8= X-Google-Smtp-Source: AA6agR7cClUSDCatrPT9FUgvkp/iEkKXYWo4duadMIVvuwxovtg6k3PR/0vMD7RwpYeFoxcctLpTcA== X-Received: by 2002:a63:204d:0:b0:42a:5e9b:44b6 with SMTP id r13-20020a63204d000000b0042a5e9b44b6mr17366133pgm.372.1661313161070; Tue, 23 Aug 2022 20:52:41 -0700 (PDT) Received: from hyeyoo ([114.29.91.56]) by smtp.gmail.com with ESMTPSA id s2-20020a170902ea0200b0016ed20eacd2sm11420310plg.150.2022.08.23.20.52.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Aug 2022 20:52:39 -0700 (PDT) Date: Wed, 24 Aug 2022 12:52:34 +0900 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Vlastimil Babka Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Marco Elver Subject: Re: [PATCH v4 17/17] mm/sl[au]b: check if large object is valid in __ksize() Message-ID: References: <20220817101826.236819-1-42.hyeyoo@gmail.com> <20220817101826.236819-18-42.hyeyoo@gmail.com> <66e25026-a86a-0157-3671-cf66eb53964c@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <66e25026-a86a-0157-3671-cf66eb53964c@suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 23, 2022 at 05:12:01PM +0200, Vlastimil Babka wrote: > On 8/17/22 12:18, Hyeonggon Yoo wrote: > > If address of large object is not beginning of folio or size of > > the folio is too small, it must be invalid. BUG() in such cases. > > > > Cc: Marco Elver > > Suggested-by: Vlastimil Babka > > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > > Reviewed-by: Vlastimil Babka > > --- > > mm/slab_common.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/mm/slab_common.c b/mm/slab_common.c > > index 9c273a5fb0d7..98d029212682 100644 > > --- a/mm/slab_common.c > > +++ b/mm/slab_common.c > > @@ -984,8 +984,11 @@ size_t __ksize(const void *object) > > > > folio = virt_to_folio(object); > > > > - if (unlikely(!folio_test_slab(folio))) > > + if (unlikely(!folio_test_slab(folio))) { > > + BUG_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE); > > + BUG_ON(object != folio_address(folio)); > > return folio_size(folio); > > + } > > > > return slab_ksize(folio_slab(folio)->slab_cache); > > } > > In light of latest Linus' rant on BUG_ON() [1] I'm changing it to WARN_ON > and return 0, as it was in v3. > > [1] https://lore.kernel.org/all/CAHk-=wiEAH+ojSpAgx_Ep=NKPWHU8AdO3V56BXcCsU97oYJ1EA@mail.gmail.com/ Okay. I'm fine with that. > > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 98d029212682..a80c3a5e194d 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -985,8 +985,10 @@ size_t __ksize(const void *object) > folio = virt_to_folio(object); > > if (unlikely(!folio_test_slab(folio))) { > - BUG_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE); > - BUG_ON(object != folio_address(folio)); > + if (WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE)) > + return 0; > + if (WARN_ON(object != folio_address(folio))) > + return 0; > return folio_size(folio); > } > > -- Thanks, Hyeonggon