From patchwork Tue Sep 26 08:07:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Greenman, Gregory" X-Patchwork-Id: 13398804 X-Patchwork-Delegate: johannes@sipsolutions.net 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 94736E7D24C for ; Tue, 26 Sep 2023 08:07:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233829AbjIZIHv (ORCPT ); Tue, 26 Sep 2023 04:07:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233838AbjIZIHu (ORCPT ); Tue, 26 Sep 2023 04:07:50 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4FC3FB for ; Tue, 26 Sep 2023 01:07:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695715663; x=1727251663; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=mz4aAs0CjLNvuyYeoxnIUSoOAqTJjhurNeKzRpiWVwY=; b=M4zrS8s4Zvbzb7symSnwHb6yr93aOOJSGmMgqr1C/Z2yERiJzyoqcNbr 2rHxw5Y6qA6jvvBnGSeoUFKCAKzZ1NwoYSYeahEBpYpmxkhqVzaR9ZWjX DHijarmU8Vw7eRPw6hGA72dqFd68sGTez4ZAzKksU2ouy/soOBwftPkYq 1el3t8HfDS/MX6gwB41FbWG6ycGj5+43+U/8AAFWdeBDxie4vCxMeYYB2 IVPld1hgFccZW7gOz5NnVZv9ge+lRlt9KLIvlQ4poAZhL8bS+2TH6wZP2 o1DY6rFe1YqyGPM0epuF/DQoLrr+/UAoILgsMvduY3OzW86EQyDzQ2jpN A==; X-IronPort-AV: E=McAfee;i="6600,9927,10843"; a="467797262" X-IronPort-AV: E=Sophos;i="6.03,177,1694761200"; d="scan'208";a="467797262" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2023 01:07:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10843"; a="698369277" X-IronPort-AV: E=Sophos;i="6.03,177,1694761200"; d="scan'208";a="698369277" Received: from nbenitzh-mobl2.ger.corp.intel.com (HELO ggreenma-mobl2.intel.com) ([10.251.178.250]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2023 01:07:41 -0700 From: gregory.greenman@intel.com To: johannes@sipsolutions.net Cc: linux-wireless@vger.kernel.org, Johannes Berg , Gregory Greenman Subject: [PATCH 4/9] wifi: iwlwifi: fix opmode start/stop race Date: Tue, 26 Sep 2023 11:07:16 +0300 Message-Id: <20230926110319.85951554fed8.I62f20f40d79d0f136fa05e46d7fc16dc437fa3db@changeid> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20230926080721.876640-1-gregory.greenman@intel.com> References: <20230926080721.876640-1-gregory.greenman@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org From: Johannes Berg There's a race when the device is unbound (maybe because the module is unloaded) while the opmode start hasn't finished yet. The complete(request_firmware_complete) after the opmode start was meant (and commented accordingly) to prevent this problem, but it's not sufficient when the opmode module is loaded after the firmware load already completed, which happens regularly now because firmware load doesn't require userspace, unlike module load. Fix this by using the existing opmode registration mutex to protected the start/stop flows against each other properly. Signed-off-by: Johannes Berg Signed-off-by: Gregory Greenman --- drivers/net/wireless/intel/iwlwifi/iwl-drv.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-drv.c b/drivers/net/wireless/intel/iwlwifi/iwl-drv.c index 41ae4fae4b8a..c4e50f204630 100644 --- a/drivers/net/wireless/intel/iwlwifi/iwl-drv.c +++ b/drivers/net/wireless/intel/iwlwifi/iwl-drv.c @@ -1,6 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause /* - * Copyright (C) 2005-2014, 2018-2021 Intel Corporation + * Copyright (C) 2005-2014, 2018-2023 Intel Corporation * Copyright (C) 2013-2015 Intel Mobile Communications GmbH * Copyright (C) 2016-2017 Intel Deutschland GmbH */ @@ -1415,6 +1415,9 @@ _iwl_op_mode_start(struct iwl_drv *drv, struct iwlwifi_opmode_table *op) struct iwl_op_mode *op_mode = NULL; int retry, max_retry = !!iwlwifi_mod_params.fw_restart * IWL_MAX_INIT_RETRY; + /* also protects start/stop from racing against each other */ + lockdep_assert_held(&iwlwifi_opmode_table_mtx); + for (retry = 0; retry <= max_retry; retry++) { #ifdef CONFIG_IWLWIFI_DEBUGFS @@ -1445,6 +1448,9 @@ _iwl_op_mode_start(struct iwl_drv *drv, struct iwlwifi_opmode_table *op) static void _iwl_op_mode_stop(struct iwl_drv *drv) { + /* also protects start/stop from racing against each other */ + lockdep_assert_held(&iwlwifi_opmode_table_mtx); + /* op_mode can be NULL if its start failed */ if (drv->op_mode) { iwl_op_mode_stop(drv->op_mode); @@ -1728,11 +1734,6 @@ static void iwl_req_fw_callback(const struct firmware *ucode_raw, void *context) } mutex_unlock(&iwlwifi_opmode_table_mtx); - /* - * Complete the firmware request last so that - * a driver unbind (stop) doesn't run while we - * are doing the start() above. - */ complete(&drv->request_firmware_complete); /* @@ -1837,11 +1838,12 @@ void iwl_drv_stop(struct iwl_drv *drv) { wait_for_completion(&drv->request_firmware_complete); + mutex_lock(&iwlwifi_opmode_table_mtx); + _iwl_op_mode_stop(drv); iwl_dealloc_ucode(drv); - mutex_lock(&iwlwifi_opmode_table_mtx); /* * List is empty (this item wasn't added) * when firmware loading failed -- in that