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Bug 620662 - net-misc/networkmanager-1.8.0: infinite loop when changing MTU
Summary: net-misc/networkmanager-1.8.0: infinite loop when changing MTU
Status: RESOLVED UPSTREAM
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: Current packages (show other bugs)
Hardware: All Linux
: Normal normal (vote)
Assignee: Gentoo Linux Gnome Desktop Team
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-06-04 00:18 UTC by cyrillic
Modified: 2018-04-22 16:07 UTC (History)
2 users (show)

See Also:
Package list:
Runtime testing required: ---

Attachments
networkmanager_looping.txt (networkmanager_looping.txt,19.71 KB, text/plain)
2017-06-04 00:19 UTC, cyrillic 		Details
disconnect_delay.patch (disconnect_delay.patch,301 bytes, patch)
2017-06-05 23:13 UTC, cyrillic 		Details | Diff
device-carrier-wait-timeout (device-carrier-wait-timeout.patch,13.43 KB, patch)
2017-11-28 12:24 UTC, Cyril 		Details | Diff
View All Add an attachment (proposed patch, testcase, etc.)

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Description cyrillic 2017-06-04 00:18:05 UTC 
networkmanager-1.8.0 + dhcpcd can no longer connect to a 9000 MTU network, but this was working with networkmanager-1.4.4 + dhcpcd.

Reproducible: Always
Comment 1 cyrillic 2017-06-04 00:19:19 UTC 
Created attachment 475130 [details]
networkmanager_looping.txt
Comment 2 Mike Gilbert gentoo-dev 2017-06-04 00:38:14 UTC 
networkmanager-1.4.4 did not have dhcpcd support enabled.

Are you able to reproduce this with dhclient or the built-in dhcp support?
Comment 3 cyrillic 2017-06-04 01:09:10 UTC 
(In reply to Mike Gilbert from comment #2)
> networkmanager-1.4.4 did not have dhcpcd support enabled.
It did after I patched the ebuild :)

> Are you able to reproduce this with dhclient or the built-in dhcp support?
I have not tried a recent version of dhclient, but in the past, it did not support changing MTU where dhcpcd did.
Comment 4 Mike Gilbert gentoo-dev 2017-06-04 02:24:19 UTC 
I would suggest you work with the upstream developers of NetworkManager and dhcpcd to resolve this.
Comment 5 cyrillic 2017-06-04 14:48:26 UTC 
I have now tried the available DHCP clients.

dhclient : ignores MTU option from server
dhcpcd : loops
internal : loops

I think one of the internal timeouts has been shortened in networkmanager-1.8.0, and it gives-up before the MTU change can complete.
Comment 6 Mike Gilbert gentoo-dev 2017-06-04 15:33:05 UTC 
(In reply to cyrillic from comment #5)

Thanks for testing.
Comment 7 cyrillic 2017-06-05 23:13:39 UTC 
Created attachment 475314 [details, diff]
disconnect_delay.patch

I am not sure if this is hardware specific, but MTU change takes right around 4 seconds for me, and relaxing this timeout completely fixes the problem I was having.

Tested on networkmanager-1.8.0 and networkmanager-9999, Intel 1Gb and 10Gb ethernet.
Comment 8 Cyril 2017-06-12 07:59:51 UTC 
Same problem here since networkmanager-1.8.0.
Intel 82567LM Gigabit
Intel 82574L Gigabit

The problem appears on all my locally configured machines with a 9000 MTU and autoconnected.
In manual connection, this works correctly.

The patch works for my case.

Thanks Cyrillic
Comment 9 Cyril 2017-11-28 12:24:57 UTC 
Created attachment 506916 [details, diff]
device-carrier-wait-timeout
Comment 11 cyrillic 2017-12-03 02:12:05 UTC 
Does this mean the timeout can now be changed in a config file somewhere ?