Link flap when adding / removing a vlan (was Re: r360902 breaks VLAN interface on if_em (82579LM))
mike tancsa
mike at sentex.net
Fri Nov 6 23:35:43 UTC 2020
On 11/6/2020 5:32 PM, Eric Joyner wrote:
> Could you reply to that issue with what you've found?
>
> Though, as far as I can recall, igb(4) devices are not supposed to do
> the iflib reset talked about in the bug, so I wouldn't expect to see a
> link flap on those.
>
Hi Eric,
I have added my findings to
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=240818
I tried it on 3 different vendor's boards. All I210 variants it seems.
I am testing with
--- if_em.c 2020-11-06 15:00:22.120953000 -0500
+++ /tmp/if_em.c 2020-11-06 14:59:55.678195000 -0500
@@ -4047,6 +4047,7 @@
{
switch (event) {
case IFLIB_RESTART_VLAN_CONFIG:
+ return (false);
default:
return (true);
}
And if fixes the problem, but not quite sure if it introduces any
regressions or other issues ?
---Mike
> - Eric
>
> On Fri, Nov 6, 2020 at 12:48 PM mike tancsa <mike at sentex.net
> <mailto:mike at sentex.net>> wrote:
>
> On 11/6/2020 2:17 PM, mike tancsa wrote:
> > On 5/31/2020 5:39 PM, Lev Serebryakov wrote:
> >> Hello Ian,
> >>
> >> Thursday, May 28, 2020, 2:45:48 AM, you wrote:
> >>
> >>> I noticed that my VLAN interfaces stopped working after a
> recent build.
> >>> tcpdump showed traffic leaving leaving and entering the
> interface but no
> >>> host on the network actually received any packets from this
> host. A
> >>> binary search led me to r360902 and indeed the following
> change fixed
> >>> the issue for me:
> >> Problem is, this change will return terrible situation when
> adding new VLAN
> >> will flap connection status.
> >>
> >> It all worked before iflib: hardware VLAN filtering worked, and
> >> adding/removing new VLAN didn't cause link to flap.
> >>
> >> Now, with iflib, looks like we can not have all good things at
> once :(
>
>
> Looks like this is captured in
>
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=240818
> <https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=240818>
>
>
> > Hi All,
> >
> > Just came across this thread as I am running into this behaviour on
> > RELENG_12. Adding a new vlan causes all vlans on the parent
> interface
> > to flap. Not the greatest thing as it bounces a LOT of traffic
> > potentially, flaps routing etc. Is there a way around this ?
> >
> > This is on r367411 releng12
> >
> > igb0 at pci0:2:0:0: class=0x020000 card=0x153315d9
> chip=0x15338086
> > rev=0x03 hdr=0x00
> > vendor = 'Intel Corporation'
> > device = 'I210 Gigabit Network Connection'
> > class = network
> > subclass = ethernet
> >
> > eg. just something simple like
> >
> > ifconfig vlan16 create 10.1.2.3/29 <http://10.1.2.3/29> vlandev
> igb1 vlan 16
> >
> > # dmesg | tail -8
> > igb1: link state changed to DOWN
> > vlan16: link state changed to DOWN
> > vlan2049: link state changed to DOWN
> > vlan15: link state changed to DOWN
> > igb1: link state changed to UP
> > vlan16: link state changed to UP
> > vlan2049: link state changed to UP
> > vlan15: link state changed to UP
> >
> >
> > ---Mike
> >
> >
> >
> >
> > _______________________________________________
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