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From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>,
	jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org,
	torvalds@linux-foundation.org, akpm@linux-foundation.org,
	indan@nul.nu, bdonlan@gmail.com
Subject: Re: [PATCH 03/10] ptrace: implement PTRACE_SEIZE
Date: Mon, 23 May 2011 14:43:14 +0200	[thread overview]
Message-ID: <20110523124314.GA7232@redhat.com> (raw)
In-Reply-To: <20110518095539.GU20624@htj.dyndns.org>

On 05/18, Tejun Heo wrote:
>
> I've been thinking about Jan's suggestion to make ATTACH and DETACH
> not require tracee to trap. We already have this for DETACH for cases
> where the tracer is killed

Yes, I still think that the new DETACH_XXX request which doesn't need
the stopped tracee makes sense. Yes, we have PTRACE_INTERRUPT. But please
recall the previous discussion, it is possible that the tracee can't
react to PTRACE_INTERRUPT and trap because it waits for other threads
we are tracing.

And. Currently there is no way to detach a zombie leader. Perhaps we
should change do_wait(), but it is not clear what should we do if the
tracer is the real parent (we already discussed this a bit).

> and it seems it wouldn't be too difficult
> to make that happen for ATTACH either

Yes, I think this is simple to do. Do we need this? I leave this up
to you and Jan.

To me personally attach-implies-trap looks more natural, but probably
gdb has another opinion.


Anyway. IIUC, gdb wants the auto-attach-on-clone without the trap,
this is more important but this opens a lot of problems.


> and for that to be truly useful
> I suppose PTRACE_SETOPTIONS shouldn't require trapped state either.

Hmm. Why? we could pass this options along with PTRACE_SEIZE?

> Jan, would that be enough for the use cases you have on mind?

Jan?

Oleg.


  parent reply	other threads:[~2011-05-23 12:44 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-16 18:17 [PATCHSET ptrace] ptrace: implement PTRACE_SEIZE/INTERRUPT and group stop notification, take#2 Tejun Heo
2011-05-16 18:17 ` [PATCH 01/10] signal: remove three noop tracehooks Tejun Heo
2011-05-17 16:22   ` Christoph Hellwig
2011-05-17 16:27     ` Tejun Heo
2011-05-18 18:45   ` Oleg Nesterov
2011-05-19 12:11     ` Tejun Heo
2011-05-19 16:10       ` Oleg Nesterov
2011-05-16 18:17 ` [PATCH 02/10] job control: introduce JOBCTL_TRAP_STOP and use it for group stop trap Tejun Heo
2011-05-18 16:48   ` Oleg Nesterov
2011-05-18 16:57     ` Oleg Nesterov
2011-05-19 10:19     ` Tejun Heo
2011-05-19 16:19       ` Oleg Nesterov
2011-05-16 18:17 ` [PATCH 03/10] ptrace: implement PTRACE_SEIZE Tejun Heo
2011-05-18  0:40   ` Denys Vlasenko
2011-05-18  9:55     ` Tejun Heo
2011-05-18 10:44       ` Denys Vlasenko
2011-05-18 11:14         ` Tejun Heo
2011-05-19 14:17       ` Tejun Heo
2011-05-19 15:02         ` Tejun Heo
2011-05-19 19:31         ` Pedro Alves
2011-05-19 22:42           ` Denys Vlasenko
2011-05-19 23:00             ` Pedro Alves
2011-05-20  1:44               ` Denys Vlasenko
2011-05-20  8:56                 ` Pedro Alves
2011-05-20  9:12                   ` Tejun Heo
2011-05-20  9:07               ` Tejun Heo
2011-05-20  9:27                 ` Pedro Alves
2011-05-20  9:31                   ` Tejun Heo
2011-05-24  9:49                     ` Pedro Alves
2011-05-24 12:00                       ` Tejun Heo
2011-05-24 12:36                         ` Pedro Alves
2011-05-24 14:02                           ` Tejun Heo
2011-05-24 14:55                             ` Pedro Alves
2011-05-25 18:18                             ` Oleg Nesterov
2011-05-26  9:10                               ` Tejun Heo
2011-05-26 10:01                                 ` Pedro Alves
2011-05-26 10:11                                   ` Tejun Heo
2011-05-26 14:55                                 ` Oleg Nesterov
2011-05-23 13:09         ` Oleg Nesterov
2011-05-23 12:43       ` Oleg Nesterov [this message]
2011-05-24 10:28         ` Tejun Heo
2011-05-25 18:29           ` Oleg Nesterov
2011-05-26  9:14             ` Tejun Heo
2011-05-26 15:01               ` Oleg Nesterov
2011-05-27 18:21                 ` Tejun Heo
2011-05-30 19:22                   ` Oleg Nesterov
     [not found]                     ` <BANLkTimupSd774N-VBoswOj+Dza=5ofvWQ@mail.gmail.com>
2011-05-31 19:08                       ` Oleg Nesterov
2011-05-31 21:32                         ` Linus Torvalds
2011-06-01 20:04                           ` Oleg Nesterov
2011-06-01  5:34                         ` Tejun Heo
2011-06-01 20:08                           ` Oleg Nesterov
2011-06-02  5:01                             ` Tejun Heo
2011-05-18 18:17   ` Oleg Nesterov
2011-05-19 10:34     ` Tejun Heo
2011-05-16 18:17 ` [PATCH 04/10] ptrace: implement PTRACE_INTERRUPT Tejun Heo
2011-05-18 18:38   ` Oleg Nesterov
2011-05-19 12:07     ` Tejun Heo
2011-05-19 16:21       ` Oleg Nesterov
2011-05-16 18:17 ` [PATCH 05/10] ptrace: restructure ptrace_getsiginfo() Tejun Heo
2011-05-16 18:17 ` [PATCH 06/10] ptrace: add siginfo.si_pt_flags Tejun Heo
2011-05-16 18:17 ` [PATCH 07/10] ptrace: make group stop state visible via PTRACE_GETSIGINFO Tejun Heo
2011-05-19 16:27   ` Oleg Nesterov
2011-05-19 16:40     ` Tejun Heo
2011-05-16 18:17 ` [PATCH 08/10] ptrace: don't let PTRACE_SETSIGINFO override __SI_TRAP siginfo Tejun Heo
2011-05-16 18:17 ` [PATCH 09/10] ptrace: add JOBCTL_BLOCK_NOTIFY Tejun Heo
2011-05-19 16:32   ` Oleg Nesterov
2011-05-19 16:44     ` Tejun Heo
2011-05-19 16:48       ` Oleg Nesterov
2011-05-19 16:58         ` Tejun Heo
2011-05-16 18:17 ` [PATCH 10/10] ptrace: implement group stop notification for ptracer Tejun Heo
2011-05-19 16:32   ` Oleg Nesterov
2011-05-19 16:57     ` Tejun Heo
2011-05-19 17:13       ` Oleg Nesterov
2011-05-19 22:48         ` Denys Vlasenko
2011-05-20  8:59           ` Tejun Heo
2011-05-23 13:34             ` Oleg Nesterov
2011-05-20  8:46         ` Tejun Heo
2011-05-19 16:58     ` Oleg Nesterov
2011-05-23 11:45       ` Oleg Nesterov
2011-05-24 13:44         ` Tejun Heo
2011-05-24 15:44           ` Tejun Heo
2011-05-26 14:44           ` Oleg Nesterov
2011-05-28  7:32             ` Tejun Heo
2011-05-18 18:50 ` [PATCHSET ptrace] ptrace: implement PTRACE_SEIZE/INTERRUPT and group stop notification, take#2 Oleg Nesterov
2011-05-19 12:08   ` Tejun Heo
2011-05-19 15:04 ` Linus Torvalds
2011-05-19 15:19   ` Tejun Heo
2011-05-19 22:45   ` Denys Vlasenko

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