Re: [Libunwind-devel] unwind user process from kernel?

[Arun Sharma]

On Mon, Sep 19, 2011 at 1:07 PM, Collin McCurdy <address@hidden> wrote:
> I am interested in using libunwind to examine, from the kernel, the stack of
> an interrupted user process (due to hardware performance counter overflow,
> for example).
>
> Would the right way to go about this be to use the remote interface via
> unw_create_addr_space() and appropriate accessor functions?  Or is there an
> easier way?  Has this been done already?

I'm not aware of anyone implementing this. It might be more efficient
to use the local interface. You'll also have the luxury of using
copy_from_user() to access the address space without worrying about
SIGSEGVs.

An alternate design for performance counters is to send a signal to
user space on counter overflow and do the unwinding in user space. I
have some sample code to share if you want to pursue this path.

 -Arun