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 58298C43334 for ; Sun, 12 Jun 2022 06:11:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234491AbiFLGLR (ORCPT ); Sun, 12 Jun 2022 02:11:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229664AbiFLGLP (ORCPT ); Sun, 12 Jun 2022 02:11:15 -0400 Received: from mail.nfschina.com (unknown [IPv6:2400:dd01:100f:2:72e2:84ff:fe10:5f45]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 90ADC5F67; Sat, 11 Jun 2022 23:11:13 -0700 (PDT) Received: from localhost (unknown [127.0.0.1]) by mail.nfschina.com (Postfix) with ESMTP id C69121E80D78; Sun, 12 Jun 2022 14:10:11 +0800 (CST) X-Virus-Scanned: amavisd-new at test.com Received: from mail.nfschina.com ([127.0.0.1]) by localhost (mail.nfschina.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cuOdn4AlAeKG; Sun, 12 Jun 2022 14:10:09 +0800 (CST) Received: from [172.30.21.244] (unknown [180.167.10.98]) (Authenticated sender: liqiong@nfschina.com) by mail.nfschina.com (Postfix) with ESMTPA id 7F34B1E80C8B; Sun, 12 Jun 2022 14:10:08 +0800 (CST) Subject: Re: [PATCH] rcu: Handle failure of memory allocation functions To: paulmck@kernel.org Cc: Davidlohr Bueso , Josh Triplett , Frederic Weisbecker , Neeraj Upadhyay , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , linux-kernel@vger.kernel.org, rcu@vger.kernel.org, hukun@nfschina.com, qixu@nfschina.com, yuzhe@nfschina.com, renyu@nfschina.com References: <20220611093055.1473-1-liqiong@nfschina.com> <20220611163432.GM1790663@paulmck-ThinkPad-P17-Gen-1> From: liqiong Message-ID: Date: Sun, 12 Jun 2022 14:11:09 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20220611163432.GM1790663@paulmck-ThinkPad-P17-Gen-1> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022年06月12日 00:34, Paul E. McKenney 写道: > On Sat, Jun 11, 2022 at 05:30:55PM +0800, Li Qiong wrote: >> Add warning when these functions (eg:kmalloc,vmalloc) fail, handle the >> failure. >> >> Signed-off-by: Li Qiong > Good catch, thank you! However... > >> --- >> kernel/rcu/rcutorture.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c >> index 7120165a9342..97f90e304ae3 100644 >> --- a/kernel/rcu/rcutorture.c >> +++ b/kernel/rcu/rcutorture.c >> @@ -1991,6 +1991,10 @@ static void rcu_torture_mem_dump_obj(void) >> >> kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); > As long as we are checking, why not also check this one? > > Thanx, Paul Hi Paul, Yes, the kmem_cache_create would fail too. I searched "kernel" directory, found that It seems all the code just check kmem_cache_alloc()， So, I ignored kmem_cache_create() . I will submit a v2 patch. Thanks, Li Qiong > >> rhp = kmem_cache_alloc(kcp, GFP_KERNEL); >> + if (WARN_ON_ONCE(!rhp)) { >> + kmem_cache_destroy(kcp); >> + return; >> + } >> pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); >> pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); >> mem_dump_obj(ZERO_SIZE_PTR); >> @@ -2007,6 +2011,8 @@ static void rcu_torture_mem_dump_obj(void) >> kmem_cache_free(kcp, rhp); >> kmem_cache_destroy(kcp); >> rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); >> + if (WARN_ON_ONCE(!rhp)) >> + return; >> pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); >> pr_alert("mem_dump_obj(kmalloc %px):", rhp); >> mem_dump_obj(rhp); >> @@ -2014,6 +2020,8 @@ static void rcu_torture_mem_dump_obj(void) >> mem_dump_obj(&rhp->func); >> kfree(rhp); >> rhp = vmalloc(4096); >> + if (WARN_ON_ONCE(!rhp)) >> + return; >> pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); >> pr_alert("mem_dump_obj(vmalloc %px):", rhp); >> mem_dump_obj(rhp); >> -- >> 2.11.0 >>