From: Denys Vlasenko <vda.linux@googlemail.com>
To: Indan Zupancic <indan@nul.nu>
Cc: Tejun Heo <tj@kernel.org>, Oleg Nesterov <oleg@redhat.com>,
Roland McGrath <roland@redhat.com>,
jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, akpm@linux-foundation.org
Subject: Re: [RFC] Proposal for ptrace improvements
Date: Wed, 2 Mar 2011 12:52:36 +0100 [thread overview]
Message-ID: <AANLkTinTaSpDk=89VoNrZBhCixX6dGdT4R=R9d=FG1=3@mail.gmail.com> (raw)
In-Reply-To: <6b211a19ed02fa7f001343fbd8e3d5a9.squirrel@webmail.greenhost.nl>
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
next prev parent reply other threads:[~2011-03-02 11:52 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-01 15:24 [RFC] Proposal for ptrace improvements Tejun Heo
2011-03-01 16:57 ` Denys Vlasenko
2011-03-01 17:09 ` Tejun Heo
2011-03-01 17:12 ` Tejun Heo
2011-03-01 17:21 ` Denys Vlasenko
2011-03-01 18:34 ` Tejun Heo
2011-03-01 23:51 ` Denys Vlasenko
2011-03-02 7:10 ` Tejun Heo
2011-03-02 5:07 ` Indan Zupancic
2011-03-02 7:44 ` Tejun Heo
2011-03-02 11:32 ` Indan Zupancic
2011-03-02 11:52 ` Denys Vlasenko [this message]
2011-03-02 14:50 ` Tejun Heo
2011-03-02 13:32 ` Oleg Nesterov
2011-03-03 0:47 ` Indan Zupancic
2011-03-03 1:30 ` Denys Vlasenko
2011-03-03 1:55 ` Indan Zupancic
2011-03-03 7:03 ` Tejun Heo
2011-03-01 19:06 ` Jan Kratochvil
2011-03-01 22:14 ` Denys Vlasenko
2011-03-02 7:28 ` Tejun Heo
2011-03-02 10:58 ` Denys Vlasenko
2011-03-04 16:14 ` Jan Kratochvil
2011-03-04 16:41 ` Denys Vlasenko
2011-03-04 17:07 ` Oleg Nesterov
2011-03-04 18:12 ` Jan Kratochvil
2011-03-05 8:47 ` Tejun Heo
2011-03-01 22:59 ` Denys Vlasenko
2011-03-02 7:32 ` Tejun Heo
2011-03-02 11:02 ` Denys Vlasenko
2011-03-02 11:23 ` Tejun Heo
2011-03-03 19:26 ` Oleg Nesterov
2011-03-01 23:16 ` Denys Vlasenko
2011-03-02 7:37 ` Tejun Heo
2011-03-02 11:21 ` Denys Vlasenko
2011-03-02 11:27 ` Tejun Heo
2011-03-02 11:48 ` Denys Vlasenko
2011-03-02 14:43 ` Tejun Heo
2011-03-02 15:16 ` Denys Vlasenko
2011-03-02 15:25 ` Tejun Heo
2011-03-03 17:34 ` Oleg Nesterov
2011-03-03 20:22 ` Oleg Nesterov
2011-03-04 8:23 ` Tejun Heo
2011-03-04 18:16 ` Oleg Nesterov
2011-03-05 8:33 ` Tejun Heo
2011-03-04 13:01 ` Denys Vlasenko
2011-03-04 13:41 ` Tejun Heo
2011-03-04 13:59 ` Denys Vlasenko
2011-03-04 14:07 ` Tejun Heo
2011-03-04 14:31 ` Denys Vlasenko
2011-03-04 14:40 ` Tejun Heo
2011-03-04 17:05 ` Denys Vlasenko
2011-03-04 17:12 ` Linus Torvalds
2011-03-04 18:59 ` Denys Vlasenko
2011-03-04 19:24 ` Linus Torvalds
2011-03-04 16:13 ` Oleg Nesterov
2011-03-04 16:30 ` Oleg Nesterov
2011-03-04 8:44 ` Tejun Heo
2011-03-04 16:01 ` Oleg Nesterov
2011-03-04 16:15 ` Tejun Heo
2011-03-04 16:26 ` Oleg Nesterov
2011-03-07 15:08 ` PTRACE_SEIZE/INTERRUPT: " Oleg Nesterov
2011-03-09 9:41 ` Tejun Heo
2011-03-09 17:30 ` Oleg Nesterov
2011-03-07 20:43 ` Roland McGrath
2011-03-09 10:28 ` Tejun Heo
2011-03-10 18:33 ` Steven Rostedt
2011-03-11 8:13 ` Tejun Heo
2011-03-11 8:22 ` Ingo Molnar
2011-03-11 9:35 ` Srikar Dronamraju
2011-03-11 9:43 ` Ingo Molnar
2011-03-14 1:03 ` Frank Ch. Eigler
2011-03-10 15:55 ` Steven Rostedt
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