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 EB245ECAAA1 for ; Mon, 12 Sep 2022 07:21:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229589AbiILHVj (ORCPT ); Mon, 12 Sep 2022 03:21:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230205AbiILHVF (ORCPT ); Mon, 12 Sep 2022 03:21:05 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6239E32053 for ; Mon, 12 Sep 2022 00:18:10 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id m10-20020a17090a730a00b001fa986fd8eeso11497407pjk.0 for ; Mon, 12 Sep 2022 00:18:10 -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:subject:date; bh=FWAgKNPfCinc6qD4niSWvgkzCEX7z6+nrY4Z/gZWqPw=; b=aB+Q8RfAzCbG3/IzAcmRHBx8p8ATtIqcqqtuUO1/4QC8QLbfCQH9UG8xfOaoy4IEET q8z1MNtlvgloGUZpLuXSf6x9qlWLDmrKoPGXIQzWXMZq2oipE+mhtNZBK/JDtppyl8J2 44mE605hN0IuF/AuI8Dip+5YDQodVDbeFL8OTT9xx5Qxrgk5adikVCR7RIfKGawSfrKB mkdHrcIlBM+qrLaVaBbDTGnoWHr9Zxlmazt1SKf3qjwOXLXxfmdmz3uNPIoZsFNzrlnc J/kD8sdpfsbcSACsDDCJ9Z9D9zrmtYUJcV5cxH5w6NNgbd/2rs4F4CLCDHMPubub+v5S mkEA== 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:subject:date; bh=FWAgKNPfCinc6qD4niSWvgkzCEX7z6+nrY4Z/gZWqPw=; b=FbSNk+c1sUNXr8uBVCMd/1Pdstk5EillJ3V3XR6dKucyOljZ2Ws45vIomTBosiHtvi WoVmnjstzmKMa4bcSUQrPOGGk74WtQo3soTdzeNxbdKRDJhUmhU/HO+win2hIZv74/OL Vao0J48HHqx2UJTMkcY1FsSOcu1sxF9/h8M5p7QZKkvMNCwo0zTUBAZD/cmI0fZqetHo LfadlYW1UQD3TZmePnPGbyz/p90AzTHwC9j7AYRCxstjHJFzDQcPcrDpwMy62vlJjo1X 6jmmIpDdH6K5KCoVt8CHvGF6X/w0uycwYB57gA3yurbUERfC6Pgiqj8VhlP5eApFYk6O LZfw== X-Gm-Message-State: ACgBeo1+NdptOVBIjJaF4adCOcOb0O26V8+tFjVWp7z0CwYnADRZmWzU e2Cm70STPU/rk//1NeZ9xmk= X-Google-Smtp-Source: AA6agR59s2thu9I42pAf4k79SXby4Cz8U1Ux40VIz0G/+JyFbLW4Mdp70WV6fkBD6X/sVpO8GdVdJw== X-Received: by 2002:a17:902:8f81:b0:178:1276:59e6 with SMTP id z1-20020a1709028f8100b00178127659e6mr12790503plo.94.1662967089533; Mon, 12 Sep 2022 00:18:09 -0700 (PDT) Received: from hyeyoo ([114.29.91.56]) by smtp.gmail.com with ESMTPSA id m17-20020a637d51000000b0042ff6b0cf4dsm4790142pgn.58.2022.09.12.00.18.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Sep 2022 00:18:08 -0700 (PDT) Date: Mon, 12 Sep 2022 16:18:03 +0900 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Ben Luo Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, vbabka@suse.cz, roman.gushchin@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slub: return 0 when object pointer is NULL Message-ID: References: <1662962379-16174-1-git-send-email-luoben@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1662962379-16174-1-git-send-email-luoben@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 12, 2022 at 01:59:39PM +0800, Ben Luo wrote: > NULL is definitly not a valid address > > Signed-off-by: Ben Luo > --- > mm/slub.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 862dbd9..50fad18 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -674,7 +674,7 @@ static inline int check_valid_pointer(struct kmem_cache *s, > void *base; > > if (!object) > - return 1; > + return 0; > > base = slab_address(slab); > object = kasan_reset_tag(object); > -- > 1.8.3.1 > Hello Ben. The return value is used to check if the @object has valid pointer in @slab. (used for debugging) the return value is 0 if valid, 1 if invalid. It does not return a pointer. So changing it to 0 because 1 is invalid address does not make sense. -- Thanks, Hyeonggon