From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
hch@infradead.org
Subject: Re: [PATCH 2/8] kill tracehook_notify_death()
Date: Thu, 23 Jun 2011 15:21:26 +0200 [thread overview]
Message-ID: <20110623132126.GA10410@redhat.com> (raw)
In-Reply-To: <20110623122253.GM30101@htj.dyndns.org>
Hi Tejun,
On 06/23, Tejun Heo wrote:
>
> Hello, Oleg.
>
> On Wed, Jun 22, 2011 at 11:08:34PM +0200, Oleg Nesterov wrote:
> > Kill tracehook_notify_death(), reimplement the logic in its caller,
> > exit_notify().
> >
> > This also fixes a minor bug, if the exiting task is the group_leader
> > and it is traced by its real_parent, tracehook_notify_death() returns
> > task->exit_signal or SIGCHLD depending on thread_group_empty(), this
> > looks strange.
>
> Maybe we should do the above in a separate patch?
Do you think this makes sense? OK, I can do this...
>
> > - if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) &&
> > + if (thread_group_leader(tsk) && tsk->exit_signal != SIGCHLD &&
>
> Hmmm... it probably depends on POV but wouldn't (exit_signal != -1 &&
> exit_signal != SIGCHLD) be easier?
I disagree.
> The logic here is about demoting
> specials sigs to SIGCHLD under certain circumstances
Yes. And what is ->exit_signal? It is in fact per-process, lives in the
group_leader's task_struct. We could move it to signal_struct.
> and the check is
> there to prevent promoting -1 to SIGCHLD.
Yes, because we should never change ->exit_signal for sub-threads.
And it doesn't make sense to check exec ids (this is again per-process,
should be cleanuped) unless the task is the group leader.
> thread_group_leader() seems
> unnecessarily indirect.
This is what I disagree with. Contrary, I think thread_group_leader() exactly
explains what do we want to check. (but once again, exec_id logic should be
cleanuped, not only in this function).
Oleg.
next prev parent reply other threads:[~2011-06-23 13:23 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-17 14:50 [PATCHSET] ptrace: kill most tracehooks Tejun Heo
2011-06-17 14:50 ` [PATCH 1/7] ptrace: kill task_ptrace() Tejun Heo
2011-06-17 14:50 ` [PATCH 2/7] ptrace: introduce ptrace_event_enabled() and simplify ptrace_event() and tracehook_prepare_clone() Tejun Heo
2011-06-17 14:50 ` [PATCH 3/7] ptrace: move SIGTRAP on exec(2) logic to ptrace_event() Tejun Heo
2011-06-20 20:25 ` Oleg Nesterov
2011-06-21 7:21 ` Tejun Heo
2011-06-21 20:40 ` Oleg Nesterov
2011-06-23 8:58 ` Tejun Heo
2011-06-17 14:50 ` [PATCH 4/7] ptrace: kill trivial tracehooks Tejun Heo
2011-06-17 14:50 ` [PATCH 5/7] ptrace: kill clone/exec tracehooks Tejun Heo
2011-06-20 20:33 ` Oleg Nesterov
2011-06-21 7:24 ` Tejun Heo
2011-06-17 14:50 ` [PATCH 6/7] ptrace: kill detah tracehooks Tejun Heo
2011-06-20 19:39 ` Oleg Nesterov
2011-06-21 20:23 ` Oleg Nesterov
2011-06-23 9:24 ` Tejun Heo
2011-06-22 21:07 ` [PATCH 0/8] kill task_detached() (Was: ptrace: kill detah tracehooks) Oleg Nesterov
2011-06-22 21:08 ` [PATCH 1/8] make do_notify_parent() return bool Oleg Nesterov
2011-06-23 9:52 ` Tejun Heo
2011-06-22 21:08 ` [PATCH 2/8] kill tracehook_notify_death() Oleg Nesterov
2011-06-23 12:22 ` Tejun Heo
2011-06-23 13:21 ` Oleg Nesterov [this message]
2011-06-23 13:27 ` Tejun Heo
2011-06-23 13:28 ` Oleg Nesterov
2011-06-23 17:06 ` Oleg Nesterov
2011-06-25 14:15 ` Tejun Heo
2011-06-26 20:51 ` Oleg Nesterov
2011-06-27 8:24 ` Tejun Heo
2011-06-27 14:21 ` Oleg Nesterov
2011-06-27 14:36 ` Tejun Heo
2011-06-22 21:08 ` [PATCH 3/8] __ptrace_detach: avoid task_detached(), check do_notify_parent() Oleg Nesterov
2011-06-23 13:25 ` Tejun Heo
2011-06-22 21:09 ` [PATCH 4/8] make do_notify_parent() __must_check, update the callers Oleg Nesterov
2011-06-23 13:38 ` Tejun Heo
2011-06-22 21:09 ` [PATCH 5/8] reparent_leader: check EXIT_DEAD instead of task_detached() Oleg Nesterov
2011-06-22 21:09 ` [PATCH 6/8] kill task_detached() Oleg Nesterov
2011-06-22 21:10 ` [PATCH 7/8] do not change dead_task->exit_signal Oleg Nesterov
2011-06-22 21:10 ` [PATCH 8/8] redefine thread_group_leader() as exit_signal >= 0 Oleg Nesterov
2011-06-23 13:56 ` Tejun Heo
2011-06-17 14:50 ` [PATCH 7/7] ptrace: s/tracehook_tracer_task()/ptrace_parent()/ Tejun Heo
2011-06-20 20:16 ` Oleg Nesterov
2011-06-21 11:44 ` John Johansen
2011-06-23 9:14 ` Tejun Heo
2011-06-20 11:16 ` [PATCHSET] ptrace: kill most tracehooks Christoph Hellwig
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