From: Oleg Nesterov <oleg@tv-sign.ru>
To: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] do_sched_setscheduler: don't take tasklist_lock
Date: Sun, 13 Aug 2006 21:21:54 +0400 [thread overview]
Message-ID: <20060813172154.GA1918@oleg> (raw)
In-Reply-To: <20060813170340.GA1913@oleg>
On 08/13, Oleg Nesterov wrote:
>
> We don't need to take tasklist_lock or disable irqs for
> find_task_by_pid() + get_task_struct(). Use RCU locks
> instead.
On the other hand, I think sched_setscheduler() does need tasklist_lock!
It is unsafe do dereference ->signal unless tasklist_lock or ->siglock
is held (or p == current). Yes, we pin the task structure, but this can't
prevent from release_task()->__exit_signal() which sets ->signal = NULL.
So, I think this patch
[PATCH] Drop tasklist lock in do_sched_setscheduler
commit e74c69f46d93d29eea0ad8647863d1c6488f0f55
is not correct.
Am I missed something?
Oleg.
prev parent reply other threads:[~2006-08-13 12:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-13 17:03 [PATCH] do_sched_setscheduler: don't take tasklist_lock Oleg Nesterov
2006-08-13 17:21 ` Oleg Nesterov [this message]
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