Re: [gentoo-user] Nameserver lookups fail on virtual server after Kernel upgrade from version 4.9 to 4.12

[Neil Bothwick <neil@stfw.net>]

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I'd try again with a clean kernel tree but using make oldconfig. It's possible the automagic stuff answered n somewhere where you need a y. 

On 19 August 2017 21:28:05 EEST, Ralph Seichter <m16+gentoo@monksofcool.net> wrote:
>It seems strange to me as I write it, but since I updated one of my
>virtual servers from Kernel version 4.9.34 to 4.12.5, the server
>(Gentoo
>Linux running as a KVM guest) is experiencing timeouts when trying to
>connect to DNS resolvers. For the Kernel update, I followed the same
>steps I used for years, like
>
>  cd /usr/src/linux
>  zcat /proc/config.gz >.config
>  make silentoldconfig (answering "no" whereever possible)
>  make ...
>
>After booting with Kernel 4.12, commands like "dig +trace www.ibm.com"
>work just fine for a while, duration depending on server load, but
>after
>some threshold is passed, all further attempts to contact resolvers
>fail
>due to timeouts.
>
>I have tried running a local, caching resolver (BIND 9) on the server,
>like I usually do, and also tried using the hoster's dedicated
>resolvers.
>With Kernel 4.12, I see timeouts in both cases. These problems do not
>occur when I boot with the 4.9 Kernel which I have been using for the
>past two months.
>
>It is also worth noting that I updated two other servers to Kernel 4.12
>without any issues, but these are "real" servers, not VMs. At this
>point
>I am searching for ways to debug the issue, vaguely suspecting some KVM
>magic behind it (without any proof). I know that Kernel 4.11 introduced
>several KVM related changes, but that's about it.
>
>I appreciate all pointers.
>
>-Ralph

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

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