From: Oleg Nesterov <oleg@redhat.com>
To: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Roland McGrath <roland@redhat.com>,
Project Archer <archer@sourceware.org>
Subject: Re: ptrace improvement: PTRACE_O_INHERIT
Date: Wed, 16 Feb 2011 19:38:00 -0000 [thread overview]
Message-ID: <20110216193044.GA15576@redhat.com> (raw)
In-Reply-To: <20110215214333.GA18086@host1.dyn.jankratochvil.net>
On 02/15, Jan Kratochvil wrote:
>
> On Tue, 15 Feb 2011 14:08:05 +0100, Oleg Nesterov wrote:
>
> > Suppose that debugger uses PTRACE_O_INHERIT and then it decides to detach
> > gracefully. It should detach per-thread, but how? /proc is very unconvenient.
> > Even if we traced all threads, we do not trace them all after we detach
> > the first thread, and that thread can clone the new threads after detach.
>
> Maybe it is obvious but it has not been heard yet.
> With PTRACE_O_THREAD_INHERIT the debugger no longer has to enumerate threads
> for ptrace operations - except for attach+detach.
>
> Could PTRACE_ATTACH_NOSTOP+PTRACE_DETACH_NOSTOP? act on the whole PID at once
> if PTRACE_O_THREAD_INHERIT is applied - already during PTRACE_ATTACH_NOSTOP?
> It is a bit overloading the *_NOSTOP meaning but it is a new PTRACE_* op.
Yes, I thought about PTRACE_ATTACH_TG / PTRACE_DETACH_TG too.
This is nontrivial to implement. We should obviously avoid the races with
clone(). Now that cred_guard_mutex is per-process, this is probably possible...
But I can't understand how we can check __ptrace_may_access() for each thread.
We should refactor this code, task_lock() is needed to pin ->mm, and ->mm
should be the same. Anyway, looks possible.
Oleg.
next prev parent reply other threads:[~2011-02-16 19:38 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-03 22:39 ptrace improvement ideas Roland McGrath
2011-02-04 18:56 ` Oleg Nesterov
2011-02-04 18:58 ` Roland McGrath
2011-02-07 21:11 ` Jan Kratochvil
2011-02-08 1:58 ` Roland McGrath
2011-02-08 20:41 ` Jan Kratochvil
2011-02-09 2:48 ` Roland McGrath
2011-02-08 21:07 ` Oleg Nesterov
2011-02-08 23:18 ` hw_breakpoint userland interface Roland McGrath
2011-02-10 21:03 ` Oleg Nesterov
2011-02-10 21:14 ` Roland McGrath
2011-02-11 20:17 ` Oleg Nesterov
2011-02-10 20:00 ` ptrace improvement: PTRACE_O_INHERIT Oleg Nesterov
2011-02-11 19:24 ` Roland McGrath
2011-02-11 20:46 ` Oleg Nesterov
2011-02-12 0:59 ` Roland McGrath
2011-02-12 19:11 ` Oleg Nesterov
2011-02-14 19:31 ` Roland McGrath
2011-02-14 19:46 ` Oleg Nesterov
2011-02-15 0:36 ` Roland McGrath
2011-02-15 13:16 ` Oleg Nesterov
2011-02-15 21:43 ` Jan Kratochvil
2011-02-15 21:56 ` Roland McGrath
2011-02-16 19:42 ` Oleg Nesterov
2011-02-16 19:45 ` Roland McGrath
2011-02-16 20:09 ` Oleg Nesterov
2011-02-16 20:16 ` Roland McGrath
2011-02-19 19:48 ` Jan Kratochvil
2011-02-19 20:37 ` Oleg Nesterov
2011-02-20 8:18 ` Jan Kratochvil
2011-02-20 21:05 ` Oleg Nesterov
2011-02-21 19:54 ` Roland McGrath
2011-02-22 19:39 ` Oleg Nesterov
2011-02-22 20:49 ` Roland McGrath
2011-02-22 21:10 ` Oleg Nesterov
2011-02-22 22:16 ` Roland McGrath
2011-02-21 19:44 ` Roland McGrath
2011-02-15 22:02 ` Roland McGrath
2011-02-16 16:02 ` Jan Kratochvil
2011-02-16 18:28 ` Roland McGrath
2011-02-16 20:00 ` Oleg Nesterov
2011-02-16 20:07 ` Roland McGrath
2011-02-16 20:32 ` Oleg Nesterov
2011-02-16 19:48 ` Oleg Nesterov
2011-02-16 20:02 ` Roland McGrath
2011-02-16 20:15 ` Oleg Nesterov
2011-02-16 20:31 ` Roland McGrath
2011-02-16 21:04 ` Oleg Nesterov
2011-02-16 21:51 ` Roland McGrath
2011-02-16 19:38 ` Oleg Nesterov [this message]
2011-02-16 19:40 ` Roland McGrath
2011-02-15 22:17 ` Roland McGrath
2011-02-16 20:48 ` Oleg Nesterov
2011-02-16 11:31 ` ptrace improvement ideas (QPassSignals) Jan Kratochvil
2011-02-16 18:36 ` Roland McGrath
2011-02-16 20:21 ` Oleg Nesterov
2011-02-18 20:24 ` Oleg Nesterov
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