From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Subject: [PATCH net] sfp: fix oops with ethtool -m Date: Tue, 18 Sep 2018 16:48:53 +0100 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Cc: Andrew Lunn , Florian Fainelli , netdev@vger.kernel.org To: "David S. Miller" Return-path: Received: from pandora.armlinux.org.uk ([78.32.30.218]:34242 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728912AbeIRVWP (ORCPT ); Tue, 18 Sep 2018 17:22:15 -0400 Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: If a network interface is created prior to the SFP socket being available, ethtool can request module information. This unfortunately leads to an oops: Unable to handle kernel NULL pointer dereference at virtual address 00000008 pgd = (ptrval) [00000008] *pgd=7c400831, *pte=00000000, *ppte=00000000 Internal error: Oops: 17 [#1] SMP ARM Modules linked in: CPU: 0 PID: 1480 Comm: ethtool Not tainted 4.19.0-rc3 #138 Hardware name: Broadcom Northstar Plus SoC PC is at sfp_get_module_info+0x8/0x10 LR is at dev_ethtool+0x218c/0x2afc Fix this by not filling in the network device's SFP bus pointer until SFP is fully bound, thereby avoiding the core calling into the SFP bus code. Fixes: ce0aa27ff3f6 ("sfp: add sfp-bus to bridge between network devices and sfp cages") Reported-by: Florian Fainelli Tested-by: Florian Fainelli Signed-off-by: Russell King --- drivers/net/phy/sfp-bus.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c index 740655261e5b..83060fb349f4 100644 --- a/drivers/net/phy/sfp-bus.c +++ b/drivers/net/phy/sfp-bus.c @@ -349,6 +349,7 @@ static int sfp_register_bus(struct sfp_bus *bus) } if (bus->started) bus->socket_ops->start(bus->sfp); + bus->netdev->sfp_bus = bus; bus->registered = true; return 0; } @@ -357,6 +358,7 @@ static void sfp_unregister_bus(struct sfp_bus *bus) { const struct sfp_upstream_ops *ops = bus->upstream_ops; + bus->netdev->sfp_bus = NULL; if (bus->registered) { if (bus->started) bus->socket_ops->stop(bus->sfp); @@ -438,7 +440,6 @@ static void sfp_upstream_clear(struct sfp_bus *bus) { bus->upstream_ops = NULL; bus->upstream = NULL; - bus->netdev->sfp_bus = NULL; bus->netdev = NULL; } @@ -467,7 +468,6 @@ struct sfp_bus *sfp_register_upstream(struct fwnode_handle *fwnode, bus->upstream_ops = ops; bus->upstream = upstream; bus->netdev = ndev; - ndev->sfp_bus = bus; if (bus->sfp) { ret = sfp_register_bus(bus); -- 2.7.4