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From: Oleg Nesterov <oleg@redhat.com>
To: Roland McGrath <roland@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>,
	Denys Vlasenko <vda.linux@googlemail.com>,
	Tejun Heo <tj@kernel.org>,
	linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
	akpm@linux-foundation.org
Subject: Re: [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH
Date: Thu, 17 Feb 2011 20:33:24 +0100	[thread overview]
Message-ID: <20110217193324.GA13661@redhat.com> (raw)
In-Reply-To: <20110217185847.5E9D31806EE@magilla.sf.frob.com>

On 02/17, Roland McGrath wrote:
>
> > OK... Yes, perhaps PTRACE_{DETACH,CONT}(SIGCONT) should override
> > SIGNAL_STOP_STOPPED too. This makes sense, and this connects to
> > the problem with SIGNAL_STOP_DEQUEUED I mentioned above.
>
> It's not at all clear this really does make sense.

Yes, I already changed my mind, see another email from me ;)

> I think this may
> reflect a (common) misunderstanding of what the SIGCONT semantics are
> (aside from ptrace).  Resuming the process is not the action of
> delivering SIGCONT.

Yes. I was confused by "for a naive/legacy debugger", somehow I missed
this doesn't work with the current code anyway, no need to add this
feature.

> So IMHO what makes most sense given what all the normal semantics are
> is that PTRACE_CONT,SIGCONT does nothing magical, and generating a
> fresh SIGCONT (i.e. kill) is the way you resume from job control stop.

Exactly.

All other things we discussed are "small details". This is the most
noticeable change.

Oleg.


  reply	other threads:[~2011-02-17 19:41 UTC|newest]

Thread overview: 160+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-28 15:08 [PATCHSET] ptrace,signal: group stop / ptrace updates Tejun Heo
2011-01-28 15:08 ` [PATCH 01/10] signal: fix SIGCONT notification code Tejun Heo
2011-01-28 15:08 ` [PATCH 02/10] ptrace: remove the extra wake_up_process() from ptrace_detach() Tejun Heo
2011-01-28 18:46   ` Roland McGrath
2011-01-31 10:38     ` Tejun Heo
2011-02-01 10:26       ` [PATCH] ptrace: use safer wake up on ptrace_detach() Tejun Heo
2011-02-01 13:40         ` Oleg Nesterov
2011-02-01 15:07           ` Tejun Heo
2011-02-01 19:17             ` Oleg Nesterov
2011-02-02  5:31             ` Roland McGrath
2011-02-02 10:35               ` Tejun Heo
2011-02-02  0:27         ` Andrew Morton
2011-02-02  5:33           ` Roland McGrath
2011-02-02  5:38             ` Andrew Morton
2011-02-02 10:34               ` Tejun Heo
2011-02-02 19:33                 ` Andrew Morton
2011-02-02 20:01                   ` Tejun Heo
2011-02-02 21:40             ` Oleg Nesterov
2011-02-02  5:29         ` Roland McGrath
2011-02-02  5:28       ` [PATCH 02/10] ptrace: remove the extra wake_up_process() from ptrace_detach() Roland McGrath
2011-01-28 15:08 ` [PATCH 03/10] signal: remove superflous try_to_freeze() loop in do_signal_stop() Tejun Heo
2011-01-28 18:46   ` Roland McGrath
2011-01-28 15:08 ` [PATCH 04/10] ptrace: kill tracehook_notify_jctl() Tejun Heo
2011-01-28 21:09   ` Roland McGrath
2011-01-28 15:08 ` [PATCH 05/10] ptrace: add @why to ptrace_stop() Tejun Heo
2011-01-28 18:48   ` Roland McGrath
2011-01-28 15:08 ` [PATCH 06/10] signal: fix premature completion of group stop when interfered by ptrace Tejun Heo
2011-01-28 21:22   ` Roland McGrath
2011-01-31 11:00     ` Tejun Heo
2011-02-02  5:44       ` Roland McGrath
2011-02-02 10:56         ` Tejun Heo
2011-01-28 15:08 ` [PATCH 07/10] signal: use GROUP_STOP_PENDING to stop once for a single group stop Tejun Heo
2011-01-28 15:08 ` [PATCH 08/10] ptrace: participate in group stop from ptrace_stop() iff the task is trapping for " Tejun Heo
2011-01-28 21:30   ` Roland McGrath
2011-01-31 11:26     ` Tejun Heo
2011-02-02  5:57       ` Roland McGrath
2011-02-02 10:53         ` Tejun Heo
2011-02-03 10:02           ` Tejun Heo
2011-02-01 19:36     ` Oleg Nesterov
2011-01-28 15:08 ` [PATCH 09/10] ptrace: make do_signal_stop() use ptrace_stop() if the task is being ptraced Tejun Heo
2011-01-28 15:08 ` [PATCH 10/10] ptrace: clean transitions between TASK_STOPPED and TRACED Tejun Heo
2011-02-03 20:41   ` [PATCH 0/1] (Was: ptrace: clean transitions between TASK_STOPPED and TRACED) Oleg Nesterov
2011-02-03 20:41     ` [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH Oleg Nesterov
2011-02-03 21:36       ` Roland McGrath
2011-02-03 21:44         ` Oleg Nesterov
2011-02-04 10:53           ` Tejun Heo
2011-02-04 13:04             ` Oleg Nesterov
2011-02-04 14:48               ` Tejun Heo
2011-02-04 17:06                 ` Oleg Nesterov
2011-02-05 13:39                   ` Tejun Heo
2011-02-07 13:42                     ` Oleg Nesterov
2011-02-07 14:11                       ` Tejun Heo
2011-02-07 15:37                         ` Oleg Nesterov
2011-02-07 16:31                           ` Tejun Heo
2011-02-07 17:48                             ` Oleg Nesterov
2011-02-09 14:18                               ` Tejun Heo
2011-02-09 14:21                                 ` Tejun Heo
2011-02-09 21:25                                 ` Oleg Nesterov
2011-02-13 23:01                                   ` Denys Vlasenko
2011-02-14  9:03                                     ` Jan Kratochvil
2011-02-14 11:39                                       ` Denys Vlasenko
2011-02-14 17:32                                         ` Oleg Nesterov
2011-02-14 16:01                                       ` Oleg Nesterov
2011-02-26  3:59                                       ` Pavel Machek
2011-02-14 15:51                                     ` Oleg Nesterov
2011-02-14 14:50                                   ` Tejun Heo
2011-02-14 18:53                                     ` Oleg Nesterov
2011-02-13 22:25                                 ` Denys Vlasenko
2011-02-14 15:13                                   ` Tejun Heo
2011-02-14 16:15                                     ` Oleg Nesterov
2011-02-14 16:33                                       ` Tejun Heo
2011-02-14 17:23                                         ` Oleg Nesterov
2011-02-14 17:20                                     ` Denys Vlasenko
2011-02-14 17:30                                       ` Tejun Heo
2011-02-14 17:45                                         ` Oleg Nesterov
2011-02-14 17:54                                         ` Denys Vlasenko
2011-02-21 15:16                                           ` Tejun Heo
2011-02-21 15:28                                             ` Oleg Nesterov
2011-02-21 16:11                                               ` [pseudo patch] ptrace should respect the group stop Oleg Nesterov
2011-02-22 16:24                                               ` [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH Tejun Heo
2011-02-24 21:08                                                 ` Oleg Nesterov
2011-02-25 15:45                                                   ` Tejun Heo
2011-02-25 17:42                                                     ` Roland McGrath
2011-02-28 15:23                                                     ` Oleg Nesterov
2011-02-14 17:51                                       ` Oleg Nesterov
2011-02-14 18:55                                         ` Denys Vlasenko
2011-02-14 19:01                                           ` Oleg Nesterov
2011-02-14 19:42                                             ` Denys Vlasenko
2011-02-14 20:01                                               ` Oleg Nesterov
2011-02-15 15:24                                                 ` Tejun Heo
2011-02-15 15:58                                                   ` Oleg Nesterov
2011-02-15 17:31                                                   ` Roland McGrath
2011-02-15 20:27                                                     ` Oleg Nesterov
2011-02-18 17:02                                                       ` Tejun Heo
2011-02-18 19:37                                                         ` Oleg Nesterov
2011-02-21 16:22                                                           ` Tejun Heo
2011-02-21 16:49                                                             ` Oleg Nesterov
2011-02-21 16:59                                                               ` Tejun Heo
2011-02-23 19:31                                                                 ` Oleg Nesterov
2011-02-25 15:10                                                                   ` Tejun Heo
2011-02-24 20:29                                                             ` Oleg Nesterov
2011-02-25 15:51                                                               ` Tejun Heo
2011-02-26  2:48                                                                 ` Denys Vlasenko
2011-02-28 12:56                                                                   ` Tejun Heo
2011-02-28 13:16                                                                     ` Denys Vlasenko
2011-02-28 13:29                                                                       ` Tejun Heo
2011-02-28 13:41                                                                         ` Denys Vlasenko
2011-02-28 13:53                                                                           ` Tejun Heo
2011-02-28 14:25                                                                             ` Denys Vlasenko
2011-02-28 14:39                                                                               ` Tejun Heo
2011-02-28 16:48                                                                                 ` Oleg Nesterov
2011-02-28 14:36                                                                   ` Oleg Nesterov
2011-02-16 21:51                                       ` Jan Kratochvil
2011-02-17  3:37                                         ` Denys Vlasenko
2011-02-17 19:19                                           ` Oleg Nesterov
2011-02-18 21:11                                             ` Jan Kratochvil
2011-02-19 20:16                                               ` Oleg Nesterov
2011-02-17 16:49                                         ` Oleg Nesterov
2011-02-17 18:58                                           ` Roland McGrath
2011-02-17 19:33                                             ` Oleg Nesterov [this message]
2011-02-18 21:34                                           ` Jan Kratochvil
2011-02-19 20:06                                             ` Oleg Nesterov
2011-02-20  9:40                                               ` Jan Kratochvil
2011-02-20 17:06                                                 ` Denys Vlasenko
2011-02-20 17:48                                                   ` Oleg Nesterov
2011-02-20 19:10                                                   ` Jan Kratochvil
2011-02-20 19:16                                                     ` Oleg Nesterov
2011-02-20 17:16                                                 ` Oleg Nesterov
2011-02-20 18:52                                                   ` Jan Kratochvil
2011-02-20 20:38                                                     ` Oleg Nesterov
2011-02-20 21:06                                                       ` `(T) stopped' preservation after _exit() [Re: [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH] Jan Kratochvil
2011-02-20 21:19                                                         ` Oleg Nesterov
2011-02-20 21:20                                                       ` [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH Jan Kratochvil
2011-02-21 14:23                                                         ` Oleg Nesterov
2011-02-23 16:44                                                           ` Jan Kratochvil
2011-02-14 15:31                                   ` Oleg Nesterov
2011-02-14 17:24                                     ` Denys Vlasenko
2011-02-14 17:39                                       ` Oleg Nesterov
2011-02-14 17:57                                         ` Denys Vlasenko
2011-02-14 18:00                                           ` Oleg Nesterov
2011-02-14 18:06                                             ` Oleg Nesterov
2011-02-14 18:59                                         ` Denys Vlasenko
2011-02-13 21:24                 ` Denys Vlasenko
2011-02-14 15:06                   ` Oleg Nesterov
2011-02-14 15:19                     ` Tejun Heo
2011-02-14 16:20                       ` Oleg Nesterov
2011-02-14 17:05                     ` Denys Vlasenko
2011-02-14 17:18                       ` Oleg Nesterov
2011-01-28 16:54 ` [PATCHSET] ptrace,signal: group stop / ptrace updates Ingo Molnar
2011-01-28 17:41   ` Thomas Gleixner
2011-01-28 18:04     ` Anca Emanuel
2011-01-28 18:36       ` Mathieu Desnoyers
2011-01-28 17:55   ` Oleg Nesterov
2011-01-28 18:29     ` Bash not reacting to Ctrl-C Ingo Molnar
2011-02-05 20:34       ` Oleg Nesterov
2011-02-07 13:08         ` Oleg Nesterov
2011-02-09  6:17           ` Michael Witten
2011-02-09 14:53             ` Ingo Molnar
2011-02-09 19:37               ` Michael Witten
2011-02-11 14:41           ` Pavel Machek

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