[Devel] crash: vz extension for OpenVZ kernels

[Vasily Averin]

Dear Dave,

I've prepared vz crash extension with commands 
useful for troubleshooting of OpenVZ kernel crashes.

Could you please review the patch and advise how it's better
to distribute this extension.

vz extension uses openVZ-specific kernel structures 
and works on OpenVZ kernels only.

It implements vzlist, vzps and ctid commands:

vzlist -- shows list of OpenVZ containers,
contains Container ID, references to ve_struct 
and parent task inside container.

crash> vzlist
     CTID     VE_STRUCT            TASK          PID  COMM
      121  ffff8801491e7000  ffff8801493d0ff0   95990  init
      123  ffff880135a37000  ffff8803fb0a3470   95924  init
      321  ffff88045a778000  ffff880400616300   95923  init
      700  ffff88019ddae000  ffff88019ddd4fb0   95882  init
      503  ffff88045a84e800  ffff8803c3c782c0   95902  init
      122  ffff8804004ea000  ffff88045612afb0   95886  init
      600  ffff88016e467000  ffff880459d653f0   95885  init
        0  ffffffff81aaa220  ffff88045e530b30       1  init


vzps  -- shows list of processes inside of specified container

crash> vzps -E 121
     CTID    PID         TASK        COMM
      121   95990  ffff8801493d0ff0  init
      121   95996  ffff8803c3e3b0f0  kthreadd/121
      121   95997  ffff8803cd3aacb0  khelper/121
      121   97267  ffff880405e4b2f0  udevd
      121   99341  ffff8803c3fd2440  syslogd
      121   99404  ffff880405e0c2c0  klogd
      121   99424  ffff8803fb0f68c0  sshd
      121   99445  ffff8801493d0500  xinetd
      121   99557  ffff8804599f9230  sendmail
      121   99568  ffff8804591b00c0  sendmail
      121   99583  ffff880203e56f30  httpd
      121   99594  ffff88016e4e01c0  crond
      121   99614  ffff8803fb26cf70  xfs
      121   99624  ffff88045a6ce2c0  saslauthd
      121   99625  ffff8801ce134ff0  saslauthd
      121  248691  ffff88040e2ee9c0  httpd

ctid -- shows ContainerID for given task
crash> ctid 99614
     CTID    PID         TASK        COMM
      121   99614  ffff8803fb26cf70  xfs


Thank you,
	Vasily Averin