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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 D9FEDC4332B for ; Sat, 4 Apr 2020 17:43:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ADF27206F5 for ; Sat, 4 Apr 2020 17:43:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="im7VgW8l" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726315AbgDDRn5 (ORCPT ); Sat, 4 Apr 2020 13:43:57 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:44414 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726222AbgDDRn5 (ORCPT ); Sat, 4 Apr 2020 13:43:57 -0400 Received: by mail-pg1-f196.google.com with SMTP id 142so5295785pgf.11; Sat, 04 Apr 2020 10:43:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=lLJurUGdgsS+mtgRNqzFKl5KqZWIBbR9k0aSi6yF66Q=; b=im7VgW8lae81R5io4Fv0YUFIDXCoQaVwrPkYEks1Tk0tbWXteRP5mKsk+d1eA6Q5tv CDno8fVV0HuwiWQV42bSyVrcIwyrPh4YPo9TC2Zxs+nFkYwJ/ZxxHOds+hxAGY+Mc85R 2QZJNqcb6Tc0r2P7RiaYWFe6U43qZ8INAWld1PgjLRWgByO00gk/k02NrEYZgYhUu6s2 QVcBMQF+DnlbIoKvOrYbRU8w92K9PDbbK1bWHvhRlLBDahzjXNbgjuwl1Y7R7tgqW00r Qvy0xcgVv2CxNF6doxlMgMKdhbbX2VLHkLY6QOvZQZj+D4eJWJGPlfukQRkHtSTZYQao cwfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=lLJurUGdgsS+mtgRNqzFKl5KqZWIBbR9k0aSi6yF66Q=; b=acoLJDdXHv/E/7bPBfUqbqQU3CN6cHiOvB3qLu8zR/LiyPzdJi8O8T53cq5XkiuxgK Pe/bUT0MLfSvFDb22fFN6lKqb6wRxGAGEOwlslBD3SeJKbeg8OsRHCdC4uHsnj535XqE M6qvfRAy10/GmMQNOJNcu/KgWAMlMdAOXM4W6b6HBaBA6x8KXEOXdeDs2rdN5ktw1jPL zPeZ29QdsMGsMk0QxwLz/6y2dc7YMmmCuRIXqV1Oj09dttxHhRcBjyfs5ZynVixEEYNZ KprGvfbbr1Y9ijUcoXE5RQnK9v9pey+zCqBmB+D2NQZHCqPyOhQrqE6FlA0jUWVilY01 401w== X-Gm-Message-State: AGi0PubwrZQXmOQR0TgD6gJZikQxTCK+bs9bzF8Md+nV1iUqlnXZI8y1 jArh9I+DEn16XPSM/eQLWS8Ck/E= X-Google-Smtp-Source: APiQypIH73zGaFt1r4jaXayPl0Dj3RagODBBhCICdzwCwBS7pKke1i3cS6I9XIipjIrigobSTzbCFg== X-Received: by 2002:a63:705d:: with SMTP id a29mr13339825pgn.304.1586022235512; Sat, 04 Apr 2020 10:43:55 -0700 (PDT) Received: from localhost.localdomain ([2402:3a80:d33:cff:f832:439c:9244:ba33]) by smtp.gmail.com with ESMTPSA id r7sm8231055pfg.38.2020.04.04.10.43.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 04 Apr 2020 10:43:54 -0700 (PDT) From: madhuparnabhowmik10@gmail.com To: gregkh@linuxfoundation.org, hariprasad.kelam@gmail.com, colin.king@canonical.com Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org, andrianov@ispras.ru, stern@rowland.harvard.edu, Madhuparna Bhowmik Subject: [PATCH v2] usb: host: u132-hcd: Remove u132_static_list and list head u132_list Date: Sat, 4 Apr 2020 23:11:02 +0530 Message-Id: <20200404174102.19862-1-madhuparnabhowmik10@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Madhuparna Bhowmik u132_static_list is a global list protected by u132_module_lock. It is read in the u132_hcd_exit() function without holding the lock thus may lead to data race. However, it turns out that this list isn't used for anything useful and thus it is okay to get rid of it. Thus, remove the u132_static_list from u132-hcd module. Also remove struct list_head u132_list from struct u132. Found by Linux Driver Verification project (linuxtesting.org). Suggested-by: Alan Stern Signed-off-by: Madhuparna Bhowmik --- v2: u132_list removed from struct u132. drivers/usb/host/u132-hcd.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/drivers/usb/host/u132-hcd.c b/drivers/usb/host/u132-hcd.c index e9209e3e6248..995bc52d2d22 100644 --- a/drivers/usb/host/u132-hcd.c +++ b/drivers/usb/host/u132-hcd.c @@ -81,7 +81,6 @@ static DECLARE_WAIT_QUEUE_HEAD(u132_hcd_wait); static struct mutex u132_module_lock; static int u132_exiting; static int u132_instances; -static struct list_head u132_static_list; /* * end of the global variables protected by u132_module_lock */ @@ -177,7 +176,6 @@ struct u132_ring { }; struct u132 { struct kref kref; - struct list_head u132_list; struct mutex sw_lock; struct mutex scheduler_lock; struct u132_platform_data *board; @@ -254,7 +252,6 @@ static void u132_hcd_delete(struct kref *kref) struct usb_hcd *hcd = u132_to_hcd(u132); u132->going += 1; mutex_lock(&u132_module_lock); - list_del_init(&u132->u132_list); u132_instances -= 1; mutex_unlock(&u132_module_lock); dev_warn(&u132->platform_dev->dev, "FREEING the hcd=%p and thus the u13" @@ -3089,7 +3086,6 @@ static int u132_probe(struct platform_device *pdev) retval = 0; hcd->rsrc_start = 0; mutex_lock(&u132_module_lock); - list_add_tail(&u132->u132_list, &u132_static_list); u132->sequence_num = ++u132_instances; mutex_unlock(&u132_module_lock); u132_u132_init_kref(u132); @@ -3192,7 +3188,6 @@ static struct platform_driver u132_platform_driver = { static int __init u132_hcd_init(void) { int retval; - INIT_LIST_HEAD(&u132_static_list); u132_instances = 0; u132_exiting = 0; mutex_init(&u132_module_lock); @@ -3213,14 +3208,9 @@ static int __init u132_hcd_init(void) module_init(u132_hcd_init); static void __exit u132_hcd_exit(void) { - struct u132 *u132; - struct u132 *temp; mutex_lock(&u132_module_lock); u132_exiting += 1; mutex_unlock(&u132_module_lock); - list_for_each_entry_safe(u132, temp, &u132_static_list, u132_list) { - platform_device_unregister(u132->platform_dev); - } platform_driver_unregister(&u132_platform_driver); printk(KERN_INFO "u132-hcd driver deregistered\n"); wait_event(u132_hcd_wait, u132_instances == 0); -- 2.17.1