How to diagnose system freezes?

[Steve Parker]

On Fri, 26 Aug 2005 23:43:25 +0200, Michael Schwendt wrote:

    On Fri, 26 Aug 2005 13:40:27 -0400, Steve Parker wrote:

> Hi,
>> 
>> I'm running FC4 (with all updates) and I'm frequently experiencing total 
>> system freezes (i.e. my only option is to reset).  I highly suspect this 
>> has to do with a third-party kernel module (Contivity VPN client v3.3 
>> from Apani) as it seems to occur only when the VPN connection is active 
>> - even though the modules are always loaded.
>> 
>> With no errors/messages in any of the system logs following a freeze 
>> (crash, lockup, insert-your-favorite-word-here), how does one go about 
>> diagnosing a problem like this?  It seems to be a common problem for 
>> many people (at least on fedoraforum.org).  Anyone?  Help would be 
>> greatly appreciated.  Is it worth submitting a bug to bugzilla if the 
>> Contivity modules are suspected?

    For starters: look into enabling System Request keys, and see
    whether you can get a reaction. Also keep running the machine with
    the screen displaying the primary virtual console to see whether
    anything is logged there. -- Michael Schwendt <mschwendt at users.sf.net> 

Well, I've gotten the System Request keys enabled (thanks Michael, cool 
feature!) but, so far, the only resolution action that seems to respond 
is (b)oot; sync and re-mount as read-only don't seem to function. I can 
also do memory dumps and task lists but I don't know what I should be 
looking for. Any hints? Any other tracing actions I can take? Thanks 
again, Steve