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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id DD5DEC5CFC1 for ; Fri, 15 Jun 2018 06:58:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 88EE5208B5 for ; Fri, 15 Jun 2018 06:58:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88EE5208B5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=atomide.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933626AbeFOG6Q (ORCPT ); Fri, 15 Jun 2018 02:58:16 -0400 Received: from muru.com ([72.249.23.125]:47306 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755699AbeFOG6O (ORCPT ); Fri, 15 Jun 2018 02:58:14 -0400 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 84CB88076; Fri, 15 Jun 2018 07:00:51 +0000 (UTC) Date: Thu, 14 Jun 2018 23:58:10 -0700 From: Tony Lindgren To: "H. Nikolaus Schaller" Cc: Linus Walleij , "open list:GPIO SUBSYSTEM" , Linux Kernel Mailing List , Discussions about the Letux Kernel , kernel@pyra-handheld.com Subject: Re: BUG: drivers/pinctrl/core: races in pinctrl_groups and deferred probing Message-ID: <20180615065810.GI112168@atomide.com> References: <20180614120157.GE112168@atomide.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * H. Nikolaus Schaller [180614 12:15]: > Hi Tony, > > > Am 14.06.2018 um 14:01 schrieb Tony Lindgren : > > > > * H. Nikolaus Schaller [180613 12:41]: > >> > >> Now if I look into pinctrl_generic_add_group() and pinctrl_generic_get_group_name(), > >> pctldev->num_groups++ is not protected if pinctrl_generic_add_group() may be called by > >> two threads in parallel for the same pctldev. Hence a second thread may try to insert > >> a different node into the radix tree at the same selector index. This fails but there > >> is no error check - and the second entry is completely missing (but probably assumed to > >> be there). > > > > Sounds like pinctrl-single.c is missing mutex around calls to > > pinctrl_generic_add_group()? > > Yes, that could be. I didn't research the call path, just the one of > devm_pinctrl_get(). That uses a mutex in In addition to missing mutex lock around the generic pinctrl functions we also have racy helpers pinctrl_generic_remove_last_group() and pinmux_generic_remove_last_function() like you pointed out. I'll post a patch for you later on today to test. Regards, Tony