[Pkg-xen-devel] Bug#880554: xen domu freezes with kernel linux-image-4.9.0-4-amd64

[Christian Schwamborn]

Hi Hans and Valentin,

first of all: Thanks for your help and explanations, that is very 
helpfull. I was on vacation last week and couldn't answer right away.

On 07.01.2018 19:36, Hans van Kranenburg wrote:
> If this is something users are going to run into while not doing more
> unusual things like having dozens of vcpus or network interfaces, then
> changing the default could prevent hours of frustration and debugging
> for them.

As a reference:

Dom0 is stretch.

0 root at zero:~# xl list
Name           ID   Mem VCPUs	State	Time(s)
Domain-0        0  1961     2     r-----  407972.8
xaver-jessie   10  2048     2     -b----  177520.8
ustrich-jessie 12  2048     2     -b----    8555.9
ourea-stretch  14  8192     2     -b----  167352.7
arriba         17  4096     2     -b----    5108.3

All DomU's have one network interface on a bridge.
xaver-jessie has 5 block devices (phys, lvm)
ustrich-jessie has 4 block devices (phys, lvm)
ourea-stretch has 16 block devices (phys, lvm)
arriba has just one (phys, lvm) and is a hvm windows system

As you can see, nothing crazy with lots of vcpus or network interfaces.

The crashing (freezing) DomU was ourea-stretch, which is the one with 
the most load (smb, some web services, cal/card dav, psql, ldap, 
postfix, cyrus ...). As mentioned, the freezes stopped after using the 
backports kernel, nothing else changed. I was desperate at that time to 
get this new installed system to work and frankly stopped all planed 
updates to stretch on other systems at that point until I know what is 
going on.

Is there a easy way to get/monitor the used 'grants' frames? As I 
understand it, the xen-diag tool you mentioned doesn't compile in xen 4.8?

Christian