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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 9A862C28CC0 for ; Wed, 29 May 2019 11:26:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 77E5B20B1F for ; Wed, 29 May 2019 11:26:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727014AbfE2L02 (ORCPT ); Wed, 29 May 2019 07:26:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59422 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726225AbfE2L02 (ORCPT ); Wed, 29 May 2019 07:26:28 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7418D75721; Wed, 29 May 2019 11:26:28 +0000 (UTC) Received: from prarit.khw1.lab.eng.bos.redhat.com (prarit-guest.khw1.lab.eng.bos.redhat.com [10.16.200.63]) by smtp.corp.redhat.com (Postfix) with ESMTP id B573B1001E86; Wed, 29 May 2019 11:26:27 +0000 (UTC) From: Prarit Bhargava To: linux-kernel@vger.kernel.org Cc: Prarit Bhargava , Barret Rhoden , David Arcari , Jessica Yu , Heiko Carstens Subject: [PATCH v3] kernel/module.c: Only return -EEXIST for modules that have finished loading Date: Wed, 29 May 2019 07:26:25 -0400 Message-Id: <20190529112625.28699-1-prarit@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Wed, 29 May 2019 11:26:28 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Microsoft HyperV disables the X86_FEATURE_SMCA bit on AMD systems, and linux guests boot with repeated errors: amd64_edac_mod: Unknown symbol amd_unregister_ecc_decoder (err -2) amd64_edac_mod: Unknown symbol amd_register_ecc_decoder (err -2) amd64_edac_mod: Unknown symbol amd_report_gart_errors (err -2) amd64_edac_mod: Unknown symbol amd_unregister_ecc_decoder (err -2) amd64_edac_mod: Unknown symbol amd_register_ecc_decoder (err -2) amd64_edac_mod: Unknown symbol amd_report_gart_errors (err -2) The warnings occur because the module code erroneously returns -EEXIST for modules that have failed to load and are in the process of being removed from the module list. module amd64_edac_mod has a dependency on module edac_mce_amd. Using modules.dep, systemd will load edac_mce_amd for every request of amd64_edac_mod. When the edac_mce_amd module loads, the module has state MODULE_STATE_UNFORMED and once the module load fails and the state becomes MODULE_STATE_GOING. Another request for edac_mce_amd module executes and add_unformed_module() will erroneously return -EEXIST even though the previous instance of edac_mce_amd has MODULE_STATE_GOING. Upon receiving -EEXIST, systemd attempts to load amd64_edac_mod, which fails because of unknown symbols from edac_mce_amd. add_unformed_module() must wait to return for any case other than MODULE_STATE_LIVE to prevent a race between multiple loads of dependent modules. Signed-off-by: Prarit Bhargava Signed-off-by: Barret Rhoden Cc: David Arcari Cc: Jessica Yu Cc: Heiko Carstens --- kernel/module.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index 6e6712b3aaf5..1e7dcbe527af 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3397,8 +3397,7 @@ static bool finished_loading(const char *name) sched_annotate_sleep(); mutex_lock(&module_mutex); mod = find_module_all(name, strlen(name), true); - ret = !mod || mod->state == MODULE_STATE_LIVE - || mod->state == MODULE_STATE_GOING; + ret = !mod || mod->state == MODULE_STATE_LIVE; mutex_unlock(&module_mutex); return ret; @@ -3588,8 +3587,7 @@ static int add_unformed_module(struct module *mod) mutex_lock(&module_mutex); old = find_module_all(mod->name, strlen(mod->name), true); if (old != NULL) { - if (old->state == MODULE_STATE_COMING - || old->state == MODULE_STATE_UNFORMED) { + if (old->state != MODULE_STATE_LIVE) { /* Wait in case it fails to load. */ mutex_unlock(&module_mutex); err = wait_event_interruptible(module_wq, -- 2.21.0