Re: CFT: vr(4)

On Sat, 16 Feb 2008, Milan Obuch wrote:

>> I have tested 4-port Rhine III(6105LOM) and I never seen this hangs. Does 
>> this also happen on other network interface too? When the system hangs, 
>> would you break into DDB and show me the output of 'show alllocks' and 
>> 'ps'?
>
> I need some tests with another box. I was not able to break into DDB. 
> Ctrl-Alt-Esc worked until hang. Hang was really hard, Ctrl-Alt-Esc did not 
> invoke DDB. I do not feel if_vr is culprit here, more probably PCI bus got 
> somehow locked, but I have no idea how could I test it currently.

FYI, there are known issues with the effectiveness of syscons ctrl-alt-esc to 
get into the debugger -- if you haven't tried with a serial break on a serial 
console, you might want to do so.  This is because syscons's interrupt handler 
acquires the Giant lock in an ithread, requiring a lot more things to be happy 
to succeed.  In constrast, sio (and friends) use fast interrupt handlers and 
no Giant lock on the way to processing the break request.  It may well be that 
a serial break doesn't get into DDB for you, but it's worth trying...

Robert N M Watson
Computer Laboratory
University of Cambridge