Messages in this thread | | | From | Denys Vlasenko <> | Date | Wed, 2 Mar 2011 12:52:36 +0100 | Subject | Re: [RFC] Proposal for ptrace improvements |
| |
On Wed, Mar 2, 2011 at 12:32 PM, Indan Zupancic <indan@nul.nu> wrote: > On Wed, March 2, 2011 08:44, Tejun Heo wrote: >> On Wed, Mar 02, 2011 at 06:07:35AM +0100, Indan Zupancic wrote: >>> I'm not sure what Denys is talking about: Currently it's impossible to >>> pass along SIGSTOP to traced processes. Quoting the ptrace manpage: >>> >>> PTRACE_CONT >>> Restarts the stopped child process. If data is nonzero and not >>> SIGSTOP, it is interpreted as a signal to be delivered to the >>> child; otherwise, no signal is delivered. >> >> AFAICS, that's not true. SIGSTOP isn't treated differently from other >> signals in the ptrace signal delivery path. Maybe it was true in the >> past. > > Well, I can't find it in the code either, but it's probably a side-effect > of how ptrace is currently implemented. Test program code below, see for > yourself. I hope it's a program bug, but perhaps it's a kernel bug, as I > seem to get two SIGSTOP events when I allow the SIGSTOP, but only one when > denying it.
This was discussed recently (again). Second SIGSTOP you see is a job control stop notification (as opposed to signal delivery notification). It's not a bug.
-- vda -- 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/
| |