Re: help on debugging kernel module in Xen

[Brendan Cully <brendan@cs.ubc.ca>]

On Friday, 12 January 2007 at 16:07, Lily Huang wrote:
> Many thanks for your help!
> 
> I tried the command "target remote 127.0.0.1:9999", and got the response:
> 
> /******************************************************************************/
> Remote debugging using 127.0.0.1:9999
> [New Thread 0]
> [Switching to Thread 0]
> 0xc01013a7 in hypercall_page ()
> warning: shared library handler failed to enable breakpoint
> <------------------ this could be a problem
> /******************************************************************************/
> 
> then, I did "br filp_open", and then "cont".
> 
> But no matter what file I opened in domU, the breakpoint is never
> encountered. It appears that the breakpoint is not activate.
> 
> I googled but cannot find answer so far.
> 
> Did you run into similar problems?

I think I'm out of answers at this point. Perhaps it's possible that
the function has been inlined or something (though that sounds like a
function pointer). You might try breaking a little higher in the call
chain. And, until you figure out what's wrong with the debugger,
printk can help you make sure you're at least triggering the code you
expect to hit the breakpoint :)