Denys Vlasenko wrote: > On Thu, Jan 26, 2012 at 11:31 AM, Jamie Lokier <jamie@xxxxxxxxxxxxx> wrote: > > Indan Zupancic wrote: > >> On Thu, January 26, 2012 02:08, Jamie Lokier wrote: > >> > Is it disambiguated by PTRACE_EVENT_EXEC happening before the execve > >> > returns, and you knowing the TID always changes to the PID? I haven't > >> > yet checked which TID gets the PTRACE_EVENT_EXEC event, but if it's > >> > not the old one, perhaps that could be changed. > >> > >> Please don't ever change the behaviour of PTRACE_EVENT_EXEC, it's > >> barely documented already, but if if ever changes it will be also > >> unreliable. > >> > >> It's still unclear if the PTRACE_EVENT_EXEC comes before or after > >> or instead of the post-execve ptrace event. > > Denis <- confused. > Was ist das "post-execve ptrace event"? I know no such thing. > I know about PTRACE_EVENT_EXEC, and "post-execve SIGTRAP". Sorry, I meant to write execve-syscall-exit event. > >> I guess before, but > >> can I count on that? If it is after then I get a stray weird > >> execve event that messes up the system call cadence. > > > > It should be *sent* before because the exec steps must finish before > > the execve() syscall "returns". > > > > I'm not sure if the events are guaranteed to be received in the same > > order as they are sent. > > All ptrace stops (events and other stops) are synchronous. > Tracee stops, tracer notices it, tracer restarts tracee, > and only after this tracee can generate next event. > Therefore ptrace stops can't get reordered. That's good to know, thanks. -- Jamie -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
