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 45399C433EF for ; Tue, 17 May 2022 03:22:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237141AbiEQDWO (ORCPT ); Mon, 16 May 2022 23:22:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236033AbiEQDWK (ORCPT ); Mon, 16 May 2022 23:22:10 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 913E822BEA; Mon, 16 May 2022 20:22:08 -0700 (PDT) Received: from dggpemm500020.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4L2Lv53BRsz923h; Tue, 17 May 2022 11:19:13 +0800 (CST) Received: from dggpemm500013.china.huawei.com (7.185.36.172) by dggpemm500020.china.huawei.com (7.185.36.49) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 17 May 2022 11:22:06 +0800 Received: from [127.0.0.1] (10.67.108.67) by dggpemm500013.china.huawei.com (7.185.36.172) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 17 May 2022 11:22:06 +0800 Message-ID: <9b3e61b8-ecab-08ff-a3b6-83d6862ead77@huawei.com> Date: Tue, 17 May 2022 11:22:04 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v4] locking/csd_lock: change csdlock_debug from early_param to __setup Content-Language: en-US To: , , , , CC: , , , , , , , , , References: <20220510094639.106661-1-chenzhongjin@huawei.com> From: Chen Zhongjin In-Reply-To: <20220510094639.106661-1-chenzhongjin@huawei.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.108.67] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500013.china.huawei.com (7.185.36.172) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/5/10 17:46, Chen Zhongjin wrote: > csdlock_debug uses early_param and static_branch_enable() to enable > csd_lock_wait feature, which triggers a panic on arm64 with config: > CONFIG_SPARSEMEM=y > CONFIG_SPARSEMEM_VMEMMAP=n > > With CONFIG_SPARSEMEM_VMEMMAP=n, __nr_to_section is called in > static_key_enable() and returns NULL which makes NULL dereference > because mem_section is initialized in sparse_init() which is later > than parse_early_param() stage. > > For powerpc this is also broken, because early_param stage is > earlier than jump_label_init() so static_key_enable won't work. > powerpc throws an warning: "static key 'xxx' used before call > to jump_label_init()". > > Thus, early_param is too early for csd_lock_wait to run > static_branch_enable(), so changes it to __setup to fix these. > > Fixes: 8d0968cc6b8f ("locking/csd_lock: Add boot parameter for controlling CSD lock debugging") > Cc: stable@vger.kernel.org > Reported-by: Chen jingwen > Signed-off-by: Chen Zhongjin > --- > Change v3 -> v4: > Fix title and description because this fix is also applied > to powerpc. > For more detailed arm64 bug report see: > https://lore.kernel.org/linux-arm-kernel/e8715911-f835-059d-27f8-cc5f5ad30a07@huawei.com/t/ > > Change v2 -> v3: > Add module name in title > > Change v1 -> v2: > Fix return 1 for __setup > --- > kernel/smp.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/smp.c b/kernel/smp.c > index 65a630f62363..381eb15cd28f 100644 > --- a/kernel/smp.c > +++ b/kernel/smp.c > @@ -174,9 +174,9 @@ static int __init csdlock_debug(char *str) > if (val) > static_branch_enable(&csdlock_debug_enabled); > > - return 0; > + return 1; > } > -early_param("csdlock_debug", csdlock_debug); > +__setup("csdlock_debug=", csdlock_debug); > > static DEFINE_PER_CPU(call_single_data_t *, cur_csd); > static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func); Ping for review. Thanks！