Messages in this thread |  | | Date | Thu, 5 Sep 2002 18:50:38 -0400 | From | Daniel Jacobowitz <> | Subject | Re: [patch] ptrace-fix-2.5.33-A1 |
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On Fri, Sep 06, 2002 at 12:39:02AM +0200, Ingo Molnar wrote: > > On Thu, 5 Sep 2002, Daniel Jacobowitz wrote: > > > If we want to do this then we'd need to fix up every ptrace > > implementation in every architecture to call the appropriate function; > > it's a separate problem. > > which code relies on having debugged children only in the ->children list > and not in the ->ptrace_children list?
Every implementation of PTRACE_TRACEME leaves them in the ->children list. They are never added to ptrace_children. Whether this is _right_ is another question.
> > > i'm not sure about this either. What happens if an (untraced) parent has > > > traced and untraced children, and does a wait4. Would it confuse the > > > debugger if the parent could get one of the traced tasks as a result in > > > wait4? And how does the debugger solve this problem? > > > > Well, it seems to me that when a traced task has an event, it should be > > reported first to the debugger - for signals this happens in do_signal - > > and then possibly to the normal parent. But I'm not sure if this > > actually happens right now or not. Worth investigating some more. > > it just cannot happen. There are only two kinds of events passed via > wait4: tracing related and exit related. An exiting task is not traced > anymore. And two tasks cannot trace the same task - so it can never happen > that wait4 wants to look at ->ptrace_children for events.
Oh. You are, of course, right.
-- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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