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From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: roland@redhat.com, linux-kernel@vger.kernel.org,
	torvalds@linux-foundation.org, akpm@linux-foundation.org
Subject: Re: [PATCH UPDATED 06/14] signal: use GROUP_STOP_PENDING to avoid stopping multiple times for a single group stop
Date: Sun, 28 Nov 2010 20:07:42 +0100	[thread overview]
Message-ID: <20101128190741.GA12896@redhat.com> (raw)
In-Reply-To: <4CF0EE11.6000206@kernel.org>

On 11/27, Tejun Heo wrote:
>
>  static int recalc_sigpending_tsk(struct task_struct *t)
>  {
> -	if (t->signal->group_stop_count > 0 ||
> +	if ((t->group_stop & GROUP_STOP_PENDING) ||

OK, this makes the intent clear.

> @@ -732,6 +732,9 @@ static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns)
>  		t = p;
>  		do {
>  			unsigned int state;
> +
> +			t->group_stop = 0;
> +

Yes.

But, afaics, this is not enough. Say, what about zap_other_threads() ?
We shouldn't allow sub-threads to stop in this case.

Basically, every time we clear ->group_stop_count we should also reset
->group_stop for every thread. Fortunately, every time we already do
while_each_thread().

Oleg.


  reply	other threads:[~2010-11-28 19:14 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 [this message]
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
2010-11-26 10:55 ` [PATCHSET RFC] ptrace,signal: sane interaction between ptrace and job control signals Tejun Heo

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