[CentOS-virt] kernel-4.9.37-29.el7 (and el6)

On 2017-07-19 02:27 AM, Piotr Gackiewicz wrote:
> On Mon, 17 Jul 2017, Johnny Hughes wrote:
>
>> Are the testing kernels (kernel-4.9.37-29.el7 and kernel-4.9.37-29.el6,
>> with the one config file change) working for everyone:
>>
>> (turn off: CONFIG_IO_STRICT_DEVMEM)
>
> Hello.
> Maybe it's not the most appropriate thread or time, but I have been
> signalling it before:
>
> 4.9.* kernels do not work well for me any more (and for other people
> neither, as I know). Last stable kernel was 4.9.13-22.
>
> Since 4.9.25-26 I do often get:
> on 3 supermicro servers (different generations):
> - memory allocation errors on Dom0 and corresponding lost lost page 
> writes
>     due to buffer I/O error on PV guests
> - after such memory allocation error od dom0 I have spotted also:
>     - NFS client hangups on guests (server not responding, still 
> trying => server OK)
>     - iptables lockups on PV guest reboot
>
> on 1 supermicro server:
> - memory allocation errors on Dom0 and SATA lockups (many, if not SATA 
> channels at
>     - once):
>     exception Emask 0x0 SAct 0x20 SErr 0x0 action 0x6 frozen
>     hard resetting link
>     failed to IDENTIFY (I/O error, err_mask=0x4)
>     then: blk_update_request: I/O error, dev sd., sector ....
>
>
> All of these machines have been tested with memtest, no detected 
> memory problems.
> No such things occur, when I boot 4.9.13-22
> Most of my guests are centos 6 x86_64, bridged.
>
> Do anyone had such problems, dealt with it somehow?
>
>
> Since spotting these errors I have done many tests, compiled and 
> tested to
> point out single code change (kernel version, patch) - no conclusions 
> yet.
>
> But one has changed much between 4.9.13 and 4.9.25: kernel size and
> configuration.
> 4.9.13 size was 6MB and 4.9.24 is 7.1MB. Many modules have been
> compiled into kernel, here is shortened, but significant list:
> - iptables (NETFILTER_XTABLES, IP_NF_FILTER, IP_NF_TARGET_REJECT)
> - SATA_AHCI
> - ATA_AHCI (PATA, what a heck?)
> - FBDEV_FRONTEND
> - HID_MAGICKMOUSE
> - HID_NTRIG
> - USB_XHCI
> - INTEL_SMARTCONNECT
>
> Do we really need these compiled into dom0 kernel?
>
> I assume, that the biggest change in size is due to yama and CRYPTO_*, 
> and
> it is not going to change.
>
> Regards,
>
>
>
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I have not done any deep digging on this, but we had xen on centos 7 on 
a couple servers for some experimental vm's.  AMD, with Tyan S2882.  
(Other then the kernel, all the packages are up to date).  The CPU's do 
not support HVM.

We host  paravirtualized centos 7 instances (stock centos 7 kernels), 
but in our testing it was rebooting even with no vm's running.

With the 4.9.23-26 (I think... would rather retest that before saying 
for sure) and 4.9.25-27 (I can confirm this) (haven't tested 4.9.34-29), 
We get periodic reboots and kernel panics.
* by I think,  we tested 2 kernels since 4.9.13-22 which had troubles so 
far, and I recall us not yet testing 4.9.34-29).

Temporary solution for us is just holding onto the 4.9.13-22 kernel.

Anyway, I suppose a simple "me too", for now.  Have not brought it up 
prior as we haven't done any of the legwork to narrow it down.

-- 
Nathan Coulson