From: Willy Tarreau w@1wt.eu
[ Upstream commit 6922110d152e56d7569616b45a1f02876cf3eb9f ]
After migrating my laptop from 4.19-LTS to 5.4-LTS a while ago I noticed that my Ethernet port to which a bond and a VLAN interface are attached appeared to remain up after resuming from suspend with the cable unplugged (and that problem still persists with 5.10-LTS).
It happens that the following happens:
- the network driver (e1000e here) prepares to suspend, calls e1000e_down() which calls netif_carrier_off() to signal that the link is going down. - netif_carrier_off() adds a link_watch event to the list of events for this device - the device is completely stopped. - the machine suspends - the cable is unplugged and the machine brought to another location - the machine is resumed - the queued linkwatch events are processed for the device - the device doesn't yet have the __LINK_STATE_PRESENT bit and its events are silently dropped - the device is resumed with its link down - the upper VLAN and bond interfaces are never notified that the link had been turned down and remain up - the only way to provoke a change is to physically connect the machine to a port and possibly unplug it.
The state after resume looks like this: $ ip -br li | egrep 'bond|eth' bond0 UP e8:6a:64:64:64:64 <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> eth0 DOWN e8:6a:64:64:64:64 <NO-CARRIER,BROADCAST,MULTICAST,SLAVE,UP> eth0.2@eth0 UP e8:6a:64:64:64:64 <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP>
Placing an explicit call to netdev_state_change() either in the suspend or the resume code in the NIC driver worked around this but the solution is not satisfying.
The issue in fact really is in link_watch that loses events while it ought not to. It happens that the test for the device being present was added by commit 124eee3f6955 ("net: linkwatch: add check for netdevice being present to linkwatch_do_dev") in 4.20 to avoid an access to devices that are not present.
Instead of dropping events, this patch proceeds slightly differently by postponing their handling so that they happen after the device is fully resumed.
Fixes: 124eee3f6955 ("net: linkwatch: add check for netdevice being present to linkwatch_do_dev") Link: https://lists.openwall.net/netdev/2018/03/15/62 Cc: Heiner Kallweit hkallweit1@gmail.com Cc: Geert Uytterhoeven geert+renesas@glider.be Cc: Florian Fainelli f.fainelli@gmail.com Signed-off-by: Willy Tarreau w@1wt.eu Link: https://lore.kernel.org/r/20210809160628.22623-1-w@1wt.eu Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/link_watch.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/core/link_watch.c b/net/core/link_watch.c index 75431ca9300f..1a455847da54 100644 --- a/net/core/link_watch.c +++ b/net/core/link_watch.c @@ -158,7 +158,7 @@ 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 && netif_device_present(dev)) { + if (dev->flags & IFF_UP) { if (netif_carrier_ok(dev)) dev_activate(dev); else @@ -204,7 +204,8 @@ static void __linkwatch_run_queue(int urgent_only) dev = list_first_entry(&wrk, struct net_device, link_watch_list); list_del_init(&dev->link_watch_list);
- if (urgent_only && !linkwatch_urgent_event(dev)) { + if (!netif_device_present(dev) || + (urgent_only && !linkwatch_urgent_event(dev))) { list_add_tail(&dev->link_watch_list, &lweventlist); continue; }