From nobody Fri May 8 05:17:47 2026 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 B7DF6C433EF for ; Tue, 10 May 2022 09:48:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239270AbiEJJwI (ORCPT ); Tue, 10 May 2022 05:52:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239222AbiEJJwE (ORCPT ); Tue, 10 May 2022 05:52:04 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C7ADE237BA6; Tue, 10 May 2022 02:48:07 -0700 (PDT) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4KyCrH2ZdKzhZ60; Tue, 10 May 2022 17:47:27 +0800 (CST) Received: from dggpemm500013.china.huawei.com (7.185.36.172) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 10 May 2022 17:48:04 +0800 Received: from ubuntu1804.huawei.com (10.67.175.36) 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, 10 May 2022 17:48:03 +0800 From: Chen Zhongjin To: , , , , CC: , , , , , , , , , , Subject: [PATCH v4] locking/csd_lock: change csdlock_debug from early_param to __setup Date: Tue, 10 May 2022 17:46:39 +0800 Message-ID: <20220510094639.106661-1-chenzhongjin@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.67.175.36] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) 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 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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=3Dy CONFIG_SPARSEMEM_VMEMMAP=3Dn With CONFIG_SPARSEMEM_VMEMMAP=3Dn, __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-cc5f5ad30a= 07@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); =20 - return 0; + return 1; } -early_param("csdlock_debug", csdlock_debug); +__setup("csdlock_debug=3D", csdlock_debug); =20 static DEFINE_PER_CPU(call_single_data_t *, cur_csd); static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func); --=20 2.17.1