From patchwork Sat May 7 08:45:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Zhongjin X-Patchwork-Id: 12841905 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E0647C433EF for ; Sat, 7 May 2022 08:47:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:CC :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=Pjp8PLwZ6rsntiBOhsqvQvGjowaqlH6qr7hBLtjWhKU=; b=jhm5wYbR9CkMyA Z4gwilAwbvE/mfR1KU/ii3bIxhfZMjTUckVylJ9/16vkYe5Z5WrwVWHfwiAHgoOJ+2HOw/TieTBSL +MGIaxjBlGIvhGFTVtydutsd4OQzh15twYYC39LjSuiQZ+T/rBV+L5RwKRwKoxinCuEqNEmyQkpx+ b6srZJ4st2MrpdlE9NxDHcnkz46PcrJsywF7mvFAliNG44NfabDYflrbUeiwVl1JP0OHLklzH0Px1 ZJpysTjqxl4J4N0Pi5tC4P9ZouW0q9e0Ajqh80tewFtuNwSTevjDtS/ysG28qRhAKs7bInLzFaeYn aiDAAoAootZLURGcVAQQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nnG5I-006XLT-8h; Sat, 07 May 2022 08:46:40 +0000 Received: from szxga03-in.huawei.com ([45.249.212.189]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nnG5D-006XJi-Vs for linux-arm-kernel@lists.infradead.org; Sat, 07 May 2022 08:46:38 +0000 Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4KwLWx0db2zXdkZ; Sat, 7 May 2022 16:41:49 +0800 (CST) Received: from dggpemm500013.china.huawei.com (7.185.36.172) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 7 May 2022 16:46:32 +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; Sat, 7 May 2022 16:46:31 +0800 From: Chen Zhongjin To: , , , CC: , , , , , , , Subject: [PATCH 5.10 v3] locking/csd_lock: fix csdlock_debug cause arm64 boot panic Date: Sat, 7 May 2022 16:45:10 +0800 Message-ID: <20220507084510.14761-1-chenzhongjin@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.67.175.36] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500013.china.huawei.com (7.185.36.172) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220507_014636_227056_D7EC84CD X-CRM114-Status: GOOD ( 10.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org csdlock_debug is a early_param to enable csd_lock_wait feature. It uses static_branch_enable in early_param which triggers a panic on arm64 with config: CONFIG_SPARSEMEM=y CONFIG_SPARSEMEM_VMEMMAP=n The log shows: Unable to handle kernel NULL pointer dereference at virtual address ", '0' , " ... Call trace: __aarch64_insn_write+0x9c/0x18c ... static_key_enable+0x1c/0x30 csdlock_debug+0x4c/0x78 do_early_param+0x9c/0xcc parse_args+0x26c/0x3a8 parse_early_options+0x34/0x40 parse_early_param+0x80/0xa4 setup_arch+0x150/0x6c8 start_kernel+0x8c/0x720 ... Kernel panic - not syncing: Oops: Fatal exception Call trace inside __aarch64_insn_write: __nr_to_section __pfn_to_page phys_to_page patch_map __aarch64_insn_write Here, with CONFIG_SPARSEMEM_VMEMMAP=n, __nr_to_section returns NULL and makes the NULL dereference because mem_section is initialized in sparse_init after parse_early_param stage. So, static_branch_enable shouldn't be used inside early_param. To avoid this, I changed it to __setup and fixed this. Reported-by: Chen jingwen Signed-off-by: Chen Zhongjin --- 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);