LOR in iflib_timer

[Stephen Hurd]

Eric van Gyzen wrote:
> Twice a day, my router hits an LOR in iflib_timer when it jumps to the 
> "hung" label.  It's running r325049 (head 3 days ago).
>
> lock order reversal:
>  1st 0xfffffe0000f36068 igb1:tx(0):call (igb1:tx(0):call) @ 
> /usr/src/sys/kern/kern_mutex.c:182
>  2nd 0xfffff80003b0c150 igb1 (iflib ctx lock) @ 
> /usr/src/sys/net/iflib.c:2139
>
> This looks like it was fixed by the big rollup.  If it was fixed by a 
> smallish commit, can that commit alone be merged to head?  If someone 
> can point me to the commit, I'd be happy to test it.
>
> Eric

I would guess it to be one of the biggest ones.  Review here: 
https://reviews.freebsd.org/D12101