NM fails with 'config-failed' despite successful MM connection

[Dan Williams]

On Thu, 2017-01-05 at 20:57 +0100, Bjørn Mork wrote:
> Bjørn Mork <bjorn at mork.no> writes:
> 
> > I don't know where it got '28' from.  Maybe cached from an earlier
> > instance of the same device?  This is a laptop which I often
> > suspend,
> > and the modem goes completely away and is rediscovered as a
> > completely
> > new USB device on every such event.
> 
> Yes, definitely a cache issue.  I don't understand why I have started
> to
> hit it only recently. I am mostly tracking Debian sid on this laptop,
> which means that NM is at v1.4.4.
> 
> Looking at the code, I got the impression that the ifindex cache
> should
> be updated by udev events in this case, since the wwan0 interface is
> removed and then re-added.
> 
> Running with 'trace' shows that the new device with ifindex 38 is
> added
> on resume:
> 
> Jan  5 20:46:31 miraculix NetworkManager[8315]: <trace>
> [1483645591.1354] platform-linux: udev-add[wwan0,38]: device added
> 
> But attempting to connect after this still fails, due to using the
> non-existing 37 ifindex:
> 
> Jan  5 20:47:00 miraculix NetworkManager[8315]: <debug>
> [1483645620.1126] device[0x563f669f5600] (cdc-wdm0): bringing up
> device
> Jan  5 20:47:00 miraculix NetworkManager[8315]: <debug>
> [1483645620.1127] platform: link: setting up '(null)' (37)
> Jan  5 20:47:00 miraculix NetworkManager[8315]: <debug>
> [1483645620.1127] platform-linux: link: change 37: flags: set 0x1/0x1
> ([up] / [up])
> Jan  5 20:47:00 miraculix NetworkManager[8315]: <debug>
> [1483645620.1128] platform-linux: do-request-link: 37 
> Jan  5 20:47:00 miraculix NetworkManager[8315]: <debug>
> [1483645620.1129] platform-linux: netlink: recvmsg: error message
> from kernel: No such device (19) for request 2900
> Jan  5 20:47:00 miraculix NetworkManager[8315]: <debug>
> [1483645620.1130] platform-linux: netlink: recvmsg: error message
> from kernel: No such device (19) for request 2901
> Jan  5 20:47:00 miraculix NetworkManager[8315]: <debug>
> [1483645620.1130] platform-linux: do-change-link[37]: failure
> changing link: failure 19 (No such device)
> Jan  5 20:47:00 miraculix NetworkManager[8315]:
> <info>  [1483645620.1131] device (cdc-wdm0): state change: config ->
> failed (reason 'config-failed') [50 120 4]
> 
> 
> Any ideas?  To me it looks like
> 
>  cache_update_link_udev (platform, ifindex, udev_device);
> 
> should be called immediately after the 'udev-add' line is logged. Why
> didn't it update the cache?

Any idea what suspend/resume support your NM is built with?  Do you see
NM log lines about "suspending" and "waking up"?

Dan