From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Babic Subject: Re: [Regression] FEC: Panic on suspend in 3.16 Date: Wed, 06 Aug 2014 17:32:41 +0200 Message-ID: <53E24A99.2020604@denx.de> References: <53E24147.4050304@parkeon.com> <53E24525.2020809@mentor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Cc: netdev@vger.kernel.org, festevam@gmail.com, "linux-arm-kernel@lists.infradead.org" To: Nathan Lynch , Martin Fuzzey Return-path: Received: from mail-out.m-online.net ([212.18.0.9]:38219 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750945AbaHFPco (ORCPT ); Wed, 6 Aug 2014 11:32:44 -0400 In-Reply-To: <53E24525.2020809@mentor.com> Sender: netdev-owner@vger.kernel.org List-ID: Hi Nathan, Martin, On 06/08/2014 17:09, Nathan Lynch wrote: > On 08/06/2014 09:52 AM, Martin Fuzzey wrote: >> Hi all, >> >> I am using the fec ethernet driver on a i.MX53 SoC. >> >> All was working fine on 3.13 but, after upgrading to 3.16 I now get a >> panic on suspend: > > Same issue reported here: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/277728.html > > a71e3c37960c (net: phy: Set the driver when registering an MDIO bus > device) has been implicated; try reverting that. > I confirm this issue (on a i.MX35). The ndev pointer is NULL in the suspend function. I added the check for the pointer: >>From 82af51e87b78000c0e038db6056c34f72a1f4045 Mon Sep 17 00:00:00 2001 From: Stefano Babic Date: Wed, 6 Aug 2014 16:37:58 +0200 Subject: [PATCH] net: fec: check for pointer in suspend/resume Check to get a valid structure to driver data in suspend/resume functions before accessing. Signed-off-by: Stefano Babic --- drivers/net/ethernet/freescale/fec_main.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 77037fd..0f5f52f 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -2659,7 +2659,12 @@ static int fec_suspend(struct device *dev) { struct net_device *ndev = dev_get_drvdata(dev); - struct fec_enet_private *fep = netdev_priv(ndev); + struct fec_enet_private *fep; + + if (!ndev) + return 0; + + fep = netdev_priv(ndev); if (netif_running(ndev)) { fec_stop(ndev); @@ -2678,9 +2683,13 @@ static int fec_resume(struct device *dev) { struct net_device *ndev = dev_get_drvdata(dev); - struct fec_enet_private *fep = netdev_priv(ndev); + struct fec_enet_private *fep; int ret; + if (!ndev) + return 0; + + fep = netdev_priv(ndev); if (fep->reg_phy) { ret = regulator_enable(fep->reg_phy); if (ret) -- 1.9.1 Even if checking the pointer is correct (I can send a formal patch if there is an agreement), I do not understand why suspend is called twice: the first time with NULL pointer, the second time with the correct pointer. Best regards, Stefano Babic -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic@denx.de =====================================================================