[Xen-users] Crashing mythtv, mysqld and NAN errors all over the place in a domain

[George Styles <ripnetuk@xxxxxxxxx>]

Hi,

Im running Suse 9.3 pro, with the supplied kernel (Linux version
2.6.11.4-20a-xen (geeko@buildhost) (gcc version 3.3.5 20050117
(prerelease) (SUSE Linux)) #1 Wed Mar 23 21:52:37 UTC 2005
)

Im also using the version of Xen supplied with Suse 9.3

Ive got 4 or 5 domains, all running perfectly, including a samba one
with heavy network traffic. All works perfectly...

Im trying to build a mythtv domain - its almost working - it can see
thje DVB cards, and can record and so on, but occasionally (usually
when MythTV is hitting the mysql database on the same domain) im
getting some wierd crashes in MythTV.
When it crashes, the process (mythbackend) says 'killed' - 

1. is is possible the kernel is killing the process because its
misbehaving? dmesg doesnt say anything like this

2. The domain is allocated 256meg of ram - just before it crashes, it
seems to have around 4 megs of ram left (using top), and loads of swap
space (but its used NO swapspace which seems suspect). If I decrease
the ram to 32meg, it does use the swapspace, but still crashes.

3. When its gone wrong, there seems to be a problem with other
services as well - sshd wont let me connect (but recovers after 5 mins
or so) and mysqld also crashes (with errors in the log that dont tell
me much - see below).

Ive tried building and installing the non-suse kernel - same thing.

4. The way I built the system is as follows (is this correct)?
a) installed Suse 9.3 onto a 3 gig root partition, with Xen installed
b) Disabled tls (mv tls tls.disabled)
c) dd'ed the partition into a disk file
d) Booted Xen pointing it as that disk file 

Like I said, I created 4 other domains that run fine.

5. Are there any Xen logs or debug stuff I can look at for clues?
dmesg doesnt reveal anything I can see is related.

6. It crashes even when I dont have the DVB cards 'passed through' to
the domain, so its not a driver issue.

7. The other thing thats happening in this domain, is that im getting
NaN (not a number) reported all over the place  (eg, in top it reports
NaN% processor usage) and mythtv keeps building queries that say to
insert NaN into a table. This seems associated with times more than
anything.

8. It looks to me a lot like the domain is running out of resources of
some kind - perhaps memory and its refusing to use the swap space for
some reason?

9. I am getting errors about the hardware clock when the domain boots,
but I expect this as I have not passed through
Help!

10. Also, sleep has bombed a couple of times, with a ASSERT error
(Assert(time > 0)) - could this be related to the 'time is going
backwards' issue?

11. Would I benefit from upgrading Xen to the latest testing version?
is this a known issue?

thanks

George

The MySQL errors are:

050516 22:43:13  mysqld restarted
050516 22:43:14  InnoDB: Started; log sequence number 0 43634
/usr/sbin/mysqld: ready for connections.
Version: '4.1.10a'  socket: '/var/lib/mysql/mysql.sock'  port: 3306 
SUSE MySQL RPM
mysqld got signal 11;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help diagnose
the problem, but since we have already crashed, something is definitely wrong
and this may fail.

key_buffer_size=16777216
read_buffer_size=258048
max_used_connections=1
max_connections=100
threads_connected=1
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size +
sort_buffer_size)*max_connections = 92783 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

thd=0x89f3ab8
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
Cannot determine thread, fp=0x42ee4c38, backtrace may not be correct.
Stack range sanity check OK, backtrace follows:
0x8168e0b
0x4005d105
0x81b01e8
0x81b0a09
0x81b3940
0x81b7e7f
0x8183306
0x8184fd1
0x8186be4
0x818753b
0x81880a7
0x40056e31
0x4028d6fa
New value of fp=(nil) failed sanity check, terminating stack trace!
Please read http://dev.mysql.com/doc/mysql/en/Using_stack_trace.html
and follow instructions on how to resolve the stack trace. Resolved
stack trace is much more helpful in diagnosing the problem, so please do
resolve it
Trying to get some variables.
Some pointers may be invalid and cause the dump to abort...
thd->query at 0x8a17428 = SELECT data FROM settings WHERE value =
"RecordChanged"
thd->thread_id=1
The manual page at http://www.mysql.com/doc/en/Crashing.html contains
information that should help you find out what is causing the crash.

Number of processes running now: 1

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