Messages in this thread | | | Date | Fri, 25 Feb 2011 16:51:42 +0100 | From | Tejun Heo <> | Subject | Re: [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH |
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Hello,
On Thu, Feb 24, 2011 at 09:29:41PM +0100, Oleg Nesterov wrote: > Damn. Today is 02/24 ;) sorry.
No need. I've been pretty lazy with this thread too. :-)
> > On Fri, Feb 18, 2011 at 08:37:09PM +0100, Oleg Nesterov wrote: > > > > > > As it currently stands, SIGSTOP/CONT while ptraced doesn't work > > > > > > And this is probably where we disagree the most. I think this is bug, > > > and this should be fixed. > > > > I don't think we disagree that it is a bug. I want to fix it too but > > we definitely seem to disagree on how. > > Yes, but I also think that the running tracee in the SIGNAL_STOP_STOPPED > process is bug by itself. IIUC, you think this is fine.
Yeap, I actually think that's the better way.
> > * ptrace, sans the odd SIGSTOP on attach which we should remove, is > > per-task. Sending out SIGCONT on PTRACE_CONT would break that. I > > really don't think that's a good idea. > > Hmm. But why do you think we should always send SIGCONT after attach?
Hmmm... my sentences were confusing. I was trying to say,
* ptrace, as it currently stands, is largely per-task. One exception is the implicit SIGSTOP which is sent on PTRACE_ATTACH but this should be replaced with a more transparent attach request which doesn't affect jctl states.
* Sending out SIGCONT on PTRACE_CONT on jctl stopped tracee adds another exception to per-task behavior, which I don't think is a good idea.
> > * PTRACE_CONT would be behaving completely differently depending on > > whether it's resuming from group stop or other traps. > > Afaics, no. It does not matter from where the tracee resumes. See > the [pseudo patch] I sent. Once again, it doesn't really work, it > only tries to explain what I mean.
I see. I'll read the patch again.
Thanks.
-- tejun
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