net: linkwatch: add check for netdevice being present to linkwatch_do_dev

When bringing down the netdevice (incl. detaching it) and calling
netif_carrier_off directly or indirectly the latter triggers an
asynchronous linkwatch event.
This linkwatch event eventually may fail to access chip registers in
the ndo_get_stats/ndo_get_stats64 callback because the device isn't
accessible any longer, see call trace in [0].

To prevent this scenario don't check for IFF_UP only, but also make
sure that the netdevice is present.

[0] https://lists.openwall.net/netdev/2018/03/15/62

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Heiner Kallweit 2018-09-18 21:55:36 +02:00 committed by David S. Miller
parent 822143acf9
commit 124eee3f69

View File

@ -155,7 +155,7 @@ static void linkwatch_do_dev(struct net_device *dev)
clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
rfc2863_policy(dev);
if (dev->flags & IFF_UP) {
if (dev->flags & IFF_UP && netif_device_present(dev)) {
if (netif_carrier_ok(dev))
dev_activate(dev);
else