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=-7.2 required=3.0 tests=BAYES_00,BIGNUM_EMAILS, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 39E50C433DB for ; Tue, 12 Jan 2021 18:08:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE0482311D for ; Tue, 12 Jan 2021 18:08:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726352AbhALSIJ (ORCPT ); Tue, 12 Jan 2021 13:08:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:57352 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726262AbhALSIJ (ORCPT ); Tue, 12 Jan 2021 13:08:09 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7E22F23123; Tue, 12 Jan 2021 18:07:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610474848; bh=yTAFqpXc+Md+lF+Ff90z1cw5WULdZyRpwhilKe7mroo=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=eVTzdC5dHvxyeFAsOHzcYfLlEfr5ump//qt35UpwE0yuwP/rohxdwtkbTapQ5B2kS Pm8PEpy7hZSqt8NdNv0T96XenBohiHqq1WqCC3VokLtsm8qwbHWSxMho0AU3H/1JXd A2XorXAtQQ1gAb9VJx94b/Ium2bpJInph1WQs+/cY12toeDTtXj/Z6DQP33Pyi5XEn T8TXBAo508UAblODSS18GTV9WIbkd48xMoiwZLXGGMDVwLyFa5Bs5UVa68RSojLAvJ KpsqgcAmR9/V9F5TUsYvjG2jS9UowrvCa9qnZehWlmnBmeZ8wH9nntL7/Or8nO9S1U F/xIlCY1jIrCA== Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 1E8C33522AC3; Tue, 12 Jan 2021 10:07:28 -0800 (PST) Date: Tue, 12 Jan 2021 10:07:28 -0800 From: "Paul E. McKenney" To: Dan Carpenter Cc: rcu@vger.kernel.org Subject: Re: [bug report] EXP rcuscale: Add crude tests for mem_dump_obj() Message-ID: <20210112180728.GJ2743@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On Tue, Jan 12, 2021 at 05:41:46PM +0300, Dan Carpenter wrote: > Hello Paul E. McKenney, > > The patch b3a539cc4d37: "EXP rcuscale: Add crude tests for > mem_dump_obj()" from Dec 7, 2020, leads to the following static > checker warning: > > kernel/rcu/rcutorture.c:1888 rcu_torture_stats() > warn: did you mean to pass the address of 'rhp' > > kernel/rcu/rcutorture.c > 1865 { > 1866 struct rcu_head *rhp; > 1867 struct kmem_cache *kcp; > 1868 static int z; > 1869 > 1870 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); > 1871 rhp = kmem_cache_alloc(kcp, GFP_KERNEL); > 1872 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); > ^^^^ > Hopefully the address of rhp doesn't change at all in this function 0_0! One would hope! The duplication makes it easier to check the output. Without it, it is necessary to get some information from the immediately preceding pr_alert() and others of it from the first pr_alert(). Thanx, Paul > 1873 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); > 1874 mem_dump_obj(ZERO_SIZE_PTR); > 1875 pr_alert("mem_dump_obj(NULL):"); > 1876 mem_dump_obj(NULL); > 1877 pr_alert("mem_dump_obj(%px):", &rhp); > 1878 mem_dump_obj(&rhp); > 1879 pr_alert("mem_dump_obj(%px):", rhp); > 1880 mem_dump_obj(rhp); > 1881 pr_alert("mem_dump_obj(%px):", &rhp->func); > 1882 mem_dump_obj(&rhp->func); > 1883 pr_alert("mem_dump_obj(%px):", &z); > 1884 mem_dump_obj(&z); > 1885 kmem_cache_free(kcp, rhp); > 1886 kmem_cache_destroy(kcp); > 1887 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); > 1888 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); > 1889 pr_alert("mem_dump_obj(kmalloc %px):", rhp); > 1890 mem_dump_obj(rhp); > 1891 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func); > 1892 mem_dump_obj(&rhp->func); > 1893 kfree(rhp); > 1894 rhp = vmalloc(4096); > 1895 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); > 1896 pr_alert("mem_dump_obj(vmalloc %px):", rhp); > 1897 mem_dump_obj(rhp); > 1898 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func); > 1899 mem_dump_obj(&rhp->func); > 1900 vfree(rhp); > 1901 } > > regards, > dan carpenter