[coyotos-dev] Status and roadmap

[Jonathan S. Shapiro]

On Mon, 2007-01-22 at 12:03 +0000, Sam Mason wrote:
> On Fri, Jan 19, 2007 at 01:31:04PM -0500, Jonathan S. Shapiro wrote:
> > On Fri, 2007-01-19 at 16:27 +0000, Sam Mason wrote:
> > > What happens if a process has designated itself as its exception handler
> > > and faults in a non-activated state, then subsequently faults in the
> > > activated state while handling the non-activated fault.
> > 
> > Doesn't matter how it got to the activated state. Since it is already in
> > the activated state, it will not receive the message until it exits the
> > activated state, which it cannot do because it has ceased to execute
> > instructions pending resolution of the execution exception.
> > 
> > So: the process ceases to execute instructions.
> 
> Otherwise known as a dead-lock, or would something intervene and kill
> off the process?  I guess in this case the kernel would be able to
> realise, but the general case seems to complicated for me.

A third-party process, notably a debugger, can intervene here by
changing the fault handler capability. At that point the fault will be
delivered to the new handler.

The kernel does not kill processes. The process in question is not using
kernel resource in any case, and can be paged out. Reclaiming the
process is the job of application-level code. In this case, the most
likely method will be to destroy the space bank, because the process
cannot respond to a "destroy yourself" request.

-- 
Jonathan S. Shapiro, Ph.D.
Managing Director
The EROS Group, LLC
+1 443 927 1719 x5100