Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757903AbcJRM3Z (ORCPT ); Tue, 18 Oct 2016 08:29:25 -0400 Received: from vps0.lunn.ch ([178.209.37.122]:47794 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753111AbcJRM3R (ORCPT ); Tue, 18 Oct 2016 08:29:17 -0400 Date: Tue, 18 Oct 2016 14:29:09 +0200 From: Andrew Lunn To: John Crispin Cc: Vivien Didelot , Florian Fainelli , "David S. Miller" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: dsa: properly disconnect the slave PHYs Message-ID: <20161018122909.GR26778@lunn.ch> References: <1476792760-60356-1-git-send-email-john@phrozen.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1476792760-60356-1-git-send-email-john@phrozen.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1179 Lines: 42 On Tue, Oct 18, 2016 at 02:12:40PM +0200, John Crispin wrote: > The shutdown code only stopped the PHYs but does not diconnect them > properly. This could lead to null pointer deref related kernel oopses > during reboot. Fix this by calling phy_disconnect() after the PHYs are > stopped. Humm, i don't follow this. The phy is disconnected in dsa_slave_destroy(). Why is that not sufficient? Also, after calling dsa_slave_close(), dsa_slave_open() can be called. But with your change, the phy has gone, so we are going to have trouble. Andrew > > Signed-off-by: John Crispin > --- > net/dsa/slave.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/net/dsa/slave.c b/net/dsa/slave.c > index 68714a5..725d9f7 100644 > --- a/net/dsa/slave.c > +++ b/net/dsa/slave.c > @@ -154,8 +154,10 @@ static int dsa_slave_close(struct net_device *dev) > struct net_device *master = p->parent->dst->master_netdev; > struct dsa_switch *ds = p->parent; > > - if (p->phy) > + if (p->phy) { > phy_stop(p->phy); > + phy_disconnect(p->phy); > + } > > dev_mc_unsync(master, dev); > dev_uc_unsync(master, dev); > -- > 1.7.10.4 >