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From: Tejun Heo <tj@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: roland@redhat.com, linux-kernel@vger.kernel.org,
	torvalds@linux-foundation.org, akpm@linux-foundation.org,
	"@sisk.plpavel@ucw.cz"@htj.dyndns.org,
	"Jan Kratochvil \"" <jan.kratochvil@redhat.com>
Subject: Re: [PATCH 14/14] ptrace: remove the extra wake_up_process() from ptrace_detach()
Date: Mon, 29 Nov 2010 14:55:20 +0100	[thread overview]
Message-ID: <4CF3B0C8.7080200@kernel.org> (raw)
In-Reply-To: <20101128204435.GE12896@redhat.com>

Hello,

On 11/28/2010 09:44 PM, Oleg Nesterov wrote:
> Today I lost the concentration at 13/14 ;)
> 
> Will continue tomorrow. As for this patch,

Eh, well, you've already found enough holes in the patchset.  It's
like a swiss cheese.  I'll update and repost.

> On 11/26, Tejun Heo wrote:
>>
>> This wake_up_process() has a turbulent history.  This is a remnant
>> from ancient ptrace implementation and patently wrong.  Commit
>> 95a3540d (ptrace_detach: the wrong wakeup breaks the ERESTARTxxx
>> logic) removed it
> 
> Yes. This obviously means I personally like this change. In fact,
> I never understood this wakeup, and I was glad to find the reason
> to send the patch.

Another thing is that the use of wake_up_process() in ptrace is rather
scary even in ptrace_resume().  It will wake up even uninterruptible
sleeps.  Is there any reason it's not just waking up
TASK_INTERRUPTIBLE | STOPPED | TRACED?

Thanks.

-- 
tejun

  reply	other threads:[~2010-11-29 13:55 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-26 10:49 [PATCHSET RFC] ptrace,signal: sane interaction between ptrace and job control signals Tejun Heo
2010-11-26 10:49 ` [PATCH 01/14] signal: fix SIGCONT notification code Tejun Heo
2010-11-26 13:49   ` Oleg Nesterov
2010-12-01  1:43   ` Roland McGrath
2010-11-26 10:49 ` [PATCH 02/14] freezer: fix a race during freezing of TASK_STOPPED tasks Tejun Heo
2010-11-26 19:40   ` Rafael J. Wysocki
2010-11-26 19:59     ` Tejun Heo
2010-11-26 10:49 ` [PATCH 03/14] freezer: remove superflous try_to_freeze() loop in do_signal_stop() Tejun Heo
2010-11-26 19:42   ` Rafael J. Wysocki
2010-11-26 10:49 ` [PATCH 04/14] signal: don't notify parent if not stopping after tracehook_notify_jctl() " Tejun Heo
2010-11-26 14:46   ` Oleg Nesterov
2010-11-26 15:04     ` Tejun Heo
2010-11-26 10:49 ` [PATCH 05/14] signal: fix premature completion of group stop when interfered by ptrace Tejun Heo
2010-11-26 15:40   ` Oleg Nesterov
2010-11-26 16:03     ` Tejun Heo
2010-11-26 10:49 ` [PATCH 06/14] signal: use GROUP_STOP_PENDING to avoid stopping multiple times for a single group stop Tejun Heo
2010-11-26 17:59   ` Oleg Nesterov
2010-11-26 18:39     ` Tejun Heo
2010-11-27 11:40   ` [PATCH UPDATED " Tejun Heo
2010-11-28 19:07     ` Oleg Nesterov
2010-11-29 13:38       ` Tejun Heo
2010-11-26 10:49 ` [PATCH 07/14] ptrace: add @why to ptrace_stop() Tejun Heo
2010-11-26 10:49 ` [PATCH 08/14] ptrace: make do_signal_stop() use ptrace_stop() if the task is being ptraced Tejun Heo
2010-11-28 19:54   ` Oleg Nesterov
2010-11-28 20:22     ` Jan Kratochvil
2010-11-28 20:53       ` Oleg Nesterov
2010-11-26 10:49 ` [PATCH 09/14] ptrace: clean transitions between TASK_STOPPED and TRACED Tejun Heo
2010-11-28 20:25   ` Oleg Nesterov
2010-11-28 20:51     ` Jan Kratochvil
2010-11-29 13:48     ` Tejun Heo
2010-11-26 10:49 ` [PATCH 10/14] ptrace: don't consume group count from ptrace_stop() Tejun Heo
2010-11-26 10:49 ` [PATCH 11/14] ptrace: make group stop notification reliable against ptrace Tejun Heo
2010-11-28 20:30   ` Oleg Nesterov
2010-11-29 13:52     ` Tejun Heo
2010-11-26 10:49 ` [PATCH 12/14] ptrace: reorganize __ptrace_unlink() and ptrace_untrace() Tejun Heo
2010-11-26 10:49 ` [PATCH 13/14] ptrace: make SIGCONT notification reliable against ptrace Tejun Heo
2010-11-26 10:49 ` [PATCH 14/14] ptrace: remove the extra wake_up_process() from ptrace_detach() Tejun Heo
2010-11-28 20:44   ` Oleg Nesterov
2010-11-29 13:55     ` Tejun Heo [this message]
2010-11-26 10:55 ` [PATCHSET RFC] ptrace,signal: sane interaction between ptrace and job control signals Tejun Heo

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