Re: [PATCH 03/10] ptrace: implement PTRACE_SEIZE

[Pedro Alves]

On Friday 20 May 2011 10:31:11, Tejun Heo wrote:
> On Fri, May 20, 2011 at 10:27:35AM +0100, Pedro Alves wrote:
> > Okay, good to hear that.  Looks like the tracer can do:
> > 
> >  SEIZE,execve,SETOPTS,'readlink /proc/pid/exe'
> > 
> > and pretend it SEIZED after the execve.
> 
> Yeap, and I was trying to say that if tracer and tracee are running on
> different CPUs, the order between SEIZE and execve isn't even well
> defined (sans the nasty automatic SIGTRAP).

I see, indeed, thanks.

A couple interface questions that just crossed my mind:

 - on a fork/vfork/clone, if PTRACE_EVENT_FORK|VFORK|CLONE have been
   enabled, will the tracer still see the new child stop with a
   SIGSTOP, or will it see a PTRACE_EVENT_INTERRUPT?

 - is PTRACE_INTERRUPT on PTRACE_TRACEME-traced-child planed to
   be allowed (for convenience)?
   A PTRACE_O_TRACEINTERRUPT, or some such PTRACE_SETOPTIONS
   option might be necessary to get PTRACE_EVENT_INTERRUPT instead
   of SIGSTOP in the point above.

-- 
Pedro Alves
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