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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 2F718C65BAE for ; Thu, 13 Dec 2018 05:38:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E14742080F for ; Thu, 13 Dec 2018 05:38:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="N5/pxAW2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E14742080F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.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 S1726986AbeLMFil (ORCPT ); Thu, 13 Dec 2018 00:38:41 -0500 Received: from mail-pl1-f176.google.com ([209.85.214.176]:35134 "EHLO mail-pl1-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726226AbeLMFik (ORCPT ); Thu, 13 Dec 2018 00:38:40 -0500 Received: by mail-pl1-f176.google.com with SMTP id p8so504966plo.2; Wed, 12 Dec 2018 21:38:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=iFjqhMle0F456IwnNhwbJveNjVhpNpNoLbO1EhKs+7s=; b=N5/pxAW2gdlOPnzHCwamRxhUV7Dccw0FOc8rM/4kLAzfnCgov5wCCmVNbVEY/3ZXwM 8iknvph6L3bbsKHaT5/xCnQT6JIsX6eHGYjA28T/G/iZRqRvtVnTpdPqZxQ28YBHoSXX tcAkm1KUBpQbXi95JZ5dZK631eV4QiXWSzv5Wbzu6c3jqZP8JFI1Vh7SlLbzNtEa4wKF H60cy+ycz5igoXzl92c28/gXDvruaJSBWlUUal6QCMsQ+yCnq/+2bQ23d3I+cH0W4ZuC 0FdMfzbRsDT3m0SABR8ctsfJVmpfNmjvpUs6Vt+KeHPe8TyOk75cd2EkHE/rvfUM/8ND puMg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=iFjqhMle0F456IwnNhwbJveNjVhpNpNoLbO1EhKs+7s=; b=O5beMuU4CUK4gQr+NmbywT1zGpOi2aWrGxck620oA1CRh1KO4c1s5O0yvYqOWM5qnM Z8REjWzNcf8PpFOZ6RC8U25aDJeiRMRSM2GBIsRxIK0lLzjYpkL4TaidkCP602T0OSsT e65koFHzDjIhmnNcbfr9Ux7urNKsVbC+cThbUV0+FZ3x0UzDiJSBw+gO76eXIpkgHoir fiua6W9UeDECI7K4vwhJERL2+JW0TW7H70JrsoxDhIEPXCT8ySagV4W7/9TAMr48YauB Nota+nDJjT7nXz0DkQ/U52kvd3j3cuKflSqinQEeucKWDNwW16dSH+D/UjtrXCxumg+j ppUw== X-Gm-Message-State: AA+aEWbU+F+d/qLndO/mBCN6e8qgUpJKuzPKbc54pgu6dtgX2xv+4hWG uvUzzCnMLpCmSyM8pXLWJ8s= X-Google-Smtp-Source: AFSGD/WmdCk5OxfqUPKAbnHbohFwc8HQcl4wLxcE3iUSl1up6skURHD3/8/EpyEkQyWjjK/4tDTEpw== X-Received: by 2002:a17:902:2a0a:: with SMTP id i10mr22011811plb.323.1544679519204; Wed, 12 Dec 2018 21:38:39 -0800 (PST) Received: from localhost ([110.70.59.213]) by smtp.gmail.com with ESMTPSA id 85sm1025757pfw.17.2018.12.12.21.38.37 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 12 Dec 2018 21:38:38 -0800 (PST) Date: Thu, 13 Dec 2018 14:38:34 +0900 From: Sergey Senozhatsky To: Peter Zijlstra Cc: Sergey Senozhatsky , Dmitry Safonov , Jiri Slaby , kernel test robot , lkp@01.org, Greg Kroah-Hartman , Mikulas Patocka , LKML , linux-serial@vger.kernel.org, Sergey Senozhatsky , Petr Mladek , Steven Rostedt , Waiman Long Subject: Re: [LKP] [tty] c96cf923a9: WARNING:possible_circular_locking_dependency_detected Message-ID: <20181213053834.GH4860@jagdpanzerIV> References: <20181211091154.GL23332@shao2-debian> <2780774e-b397-dcc2-6950-cccb527d5014@arista.com> <20181212034252.GD431@jagdpanzerIV> <20181212090751.GU5289@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181212090751.GU5289@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (12/12/18 10:07), Peter Zijlstra wrote: > > + uart_port_lock(state, flags); > > + xmit_buf = state->xmit.buf; > > + state->xmit.buf = NULL; > > + uart_port_unlock(uport, flags); > > + > > /* > > * Free the transmit buffer page. > > */ > > - uart_port_lock(state, flags); > > - if (state->xmit.buf) { > > - free_page((unsigned long)state->xmit.buf); > > - state->xmit.buf = NULL; > > - } > > - uart_port_unlock(uport, flags); > > + if (xmit_buf) > > + free_page((unsigned long)xmit_buf); > > } > > That looks sensible anyhow. One should strive to not do alloc or free > under locks as much as possible anyway. Right, good point. -ss