netdev - [PATCH RFC v2 29/32] dsa: slave: Don't reference NULL pointer during phy

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Message-Id: <1456677700-23027-30-git-send-email-andrew@lunn.ch>
Date:	Sun, 28 Feb 2016 17:41:37 +0100
From:	Andrew Lunn <andrew@...n.ch>
To:	Florian Fainelli <f.fainelli@...il.com>,
	Vivien Didelot <vivien.didelot@...oirfairelinux.com>,
	netdev <netdev@...r.kernel.org>
Cc:	Andrew Lunn <andrew@...n.ch>
Subject: [PATCH RFC v2 29/32] dsa: slave: Don't reference NULL pointer during phy_disconnect

When the phy is disconnected, the parent pointer to the netdev it was
attached to is set to NULL. The code then tries to suspend the phy,
but dsa_slave_fixed_link_update needs the parent pointer to determine
which switch the phy is connected to. So it dereferenced a NULL
pointer. Check for this condition.

Signed-off-by: Andrew Lunn <andrew@...n.ch>
---
 net/dsa/slave.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 40b9ca72aae3..d0d29f73e2f2 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -982,11 +982,15 @@ static void dsa_slave_adjust_link(struct net_device *dev)
 static int dsa_slave_fixed_link_update(struct net_device *dev,
 				       struct fixed_phy_status *status)
 {
-	struct dsa_slave_priv *p = netdev_priv(dev);
-	struct dsa_switch *ds = p->parent;
+	struct dsa_slave_priv *p;
+	struct dsa_switch *ds;
 
-	if (ds->drv->fixed_link_update)
-		ds->drv->fixed_link_update(ds, p->port, status);
+	if (dev) {
+		p = netdev_priv(dev);
+		ds = p->parent;
+		if (ds->drv->fixed_link_update)
+			ds->drv->fixed_link_update(ds, p->port, status);
+	}
 
 	return 0;
 }
-- 
2.7.0