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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 836B6C43382 for ; Wed, 26 Sep 2018 09:27:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 257ED2086E for ; Wed, 26 Sep 2018 09:27:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 257ED2086E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.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 S1728207AbeIZPjW (ORCPT ); Wed, 26 Sep 2018 11:39:22 -0400 Received: from mail.bootlin.com ([62.4.15.54]:39220 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727157AbeIZPjW (ORCPT ); Wed, 26 Sep 2018 11:39:22 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id 8F3E1206FF; Wed, 26 Sep 2018 11:27:17 +0200 (CEST) Received: from localhost (242.171.71.37.rev.sfr.net [37.71.171.242]) by mail.bootlin.com (Postfix) with ESMTPSA id DA8AF208A1; Wed, 26 Sep 2018 11:27:05 +0200 (CEST) Date: Wed, 26 Sep 2018 11:27:06 +0200 From: Alexandre Belloni To: Olof Johansson Cc: Li Yang , Roy Pledge , linuxppc-dev , Linux ARM Mailing List , Linux Kernel Mailing List Subject: Re: [PATCH 1/2] soc: fsl: qbman: qman_portal: defer probing when qman is not available Message-ID: <20180926092706.GA16644@piout.net> References: <20180823213600.23426-1-alexandre.belloni@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/09/2018 21:45:56+0200, Olof Johansson wrote: > Hi, > > > On Thu, Aug 23, 2018 at 11:36 PM Alexandre Belloni > wrote: > > > > If the qman driver (qman_ccsr) doesn't probe or fail to probe before > > qman_portal, qm_ccsr_start will be either NULL or a stale pointer to an > > unmapped page. > > > > This leads to a crash when probing qman_portal as the init_pcfg function > > calls qman_liodn_fixup that tries to read qman registers. > > > > Assume that qman didn't probe when the pool mask is 0. > > > > Signed-off-by: Alexandre Belloni > > --- > > drivers/soc/fsl/qbman/qman_portal.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/soc/fsl/qbman/qman_portal.c b/drivers/soc/fsl/qbman/qman_portal.c > > index a120002b630e..4fc80d2c8feb 100644 > > --- a/drivers/soc/fsl/qbman/qman_portal.c > > +++ b/drivers/soc/fsl/qbman/qman_portal.c > > @@ -277,6 +277,8 @@ static int qman_portal_probe(struct platform_device *pdev) > > } > > > > pcfg->pools = qm_get_pools_sdqcr(); > > + if (pcfg->pools == 0) > > + return -EPROBE_DEFER; > > This is quite late in the probe, after a bunch of resources have been claimed. > > Note that the ioremaps above this are doing unwinds, and you'll end up > doing duplicate ioremaps if you come in and probe again. > > You should probably unwind those allocations, or move them to devm_* > or do this check earlier in the function. > The actual chance of having that happen is quite small (this was coming from a non working DT) and I mainly wanted to avoid a crash so the platform could still boot. I would think moving to devm_ would be the right thing to do. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com