From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ivan Khoronzhuk Subject: Re: [PATCH] net: ethernet: ti: cpsw: fix NULL pointer dereference in switch mode Date: Wed, 1 Feb 2017 18:30:49 +0200 Message-ID: <20170201163048.GA15402@khorivan> References: <20170131200404.29150-1-grygorii.strashko@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "David S. Miller" , netdev@vger.kernel.org, Sekhar Nori , linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org To: Grygorii Strashko Return-path: Received: from mail-lf0-f47.google.com ([209.85.215.47]:32921 "EHLO mail-lf0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752722AbdBAQay (ORCPT ); Wed, 1 Feb 2017 11:30:54 -0500 Received: by mail-lf0-f47.google.com with SMTP id x1so144650563lff.0 for ; Wed, 01 Feb 2017 08:30:53 -0800 (PST) Content-Disposition: inline In-Reply-To: <20170131200404.29150-1-grygorii.strashko@ti.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Jan 31, 2017 at 02:04:04PM -0600, Grygorii Strashko wrote: > In switch mode on struct cpsw_slave->ndev field will be initialized with > proper value only for the one cpsw slave port, as result > cpsw_get_usage_count() will generate "Unable to handle kernel NULL pointer > dereference" exception when first ethernet interface is opening > cpsw_ndo_open(). This issue causes boot regression on AM335x EVM and > reproducible on am57xx-evm (switch mode). > Fix it by adding additional check for !cpsw->slaves[i].ndev in > cpsw_get_usage_count(). > > Cc: Ivan Khoronzhuk > fixes: 03fd01ad0eea ("net: ethernet: ti: cpsw: don't duplicate ndev_running") > Signed-off-by: Grygorii Strashko > --- Yes, unfortunately forgot to add it. Thanks. Reviewed-by: Ivan Khoronzhuk > drivers/net/ethernet/ti/cpsw.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c > index 67b7323..35a95dc 100644 > --- a/drivers/net/ethernet/ti/cpsw.c > +++ b/drivers/net/ethernet/ti/cpsw.c > @@ -677,7 +677,7 @@ static int cpsw_get_usage_count(struct cpsw_common *cpsw) > u32 usage_count = 0; > > for (i = 0; i < cpsw->data.slaves; i++) > - if (netif_running(cpsw->slaves[i].ndev)) > + if (cpsw->slaves[i].ndev && netif_running(cpsw->slaves[i].ndev)) > usage_count++; > > return usage_count; > -- > 2.10.1.dirty >