From: Oleg Nesterov <oleg@tv-sign.ru>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
Andrew Morton <akpm@linux-foundation.org>,
Gautham R Shenoy <ego@in.ibm.com>,
LKML <linux-kernel@vger.kernel.org>, Pavel Machek <pavel@ucw.cz>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH 1/7] Freezer: Read PF_BORROWED_MM in a nonracy way
Date: Sat, 12 May 2007 03:20:24 +0400 [thread overview]
Message-ID: <20070511232024.GA489@tv-sign.ru> (raw)
In-Reply-To: <alpine.LFD.0.98.0705111555090.3986@woody.linux-foundation.org>
On 05/11, Linus Torvalds wrote:
>
> On Fri, 11 May 2007, Rafael J. Wysocki wrote:
> >
> > Therefore, by taking the task_lock() here we make sure that the condition
> > is alyways false when we check it for kernel threads.
>
> Why *test* it then and return anything?
>
> Why not just doa "task_lock(p); task_unlock(p);" with no return value?
because we should not freeze a kernel thread at FREEZER_USER_SPACE stage?
without task_lock() we can see "p->mm != NULL" but not PF_BORROWED_MM.
Oleg.
next prev parent reply other threads:[~2007-05-11 23:20 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-10 22:35 [PATCH 0/7] Freezer bugfixes Rafael J. Wysocki
2007-05-10 22:36 ` [PATCH 1/7] Freezer: Read PF_BORROWED_MM in a nonracy way Rafael J. Wysocki
2007-05-11 19:39 ` Andrew Morton
2007-05-11 20:21 ` Oleg Nesterov
2007-05-11 20:40 ` Rafael J. Wysocki
2007-05-11 22:56 ` Linus Torvalds
2007-05-11 23:20 ` Oleg Nesterov [this message]
2007-05-11 23:32 ` Linus Torvalds
2007-05-11 23:48 ` Oleg Nesterov
2007-05-12 0:05 ` Oleg Nesterov
2007-05-12 0:08 ` Linus Torvalds
2007-05-12 0:40 ` Oleg Nesterov
2007-05-12 1:01 ` Oleg Nesterov
2007-05-12 1:24 ` Linus Torvalds
2007-05-12 9:01 ` Rafael J. Wysocki
2007-05-12 10:45 ` Rafael J. Wysocki
2007-05-12 14:18 ` Oleg Nesterov
2007-05-12 16:35 ` Rafael J. Wysocki
2007-05-12 16:58 ` Oleg Nesterov
2007-05-12 17:16 ` Rafael J. Wysocki
2007-05-12 17:43 ` Oleg Nesterov
2007-05-12 1:11 ` Rafael J. Wysocki
2007-05-11 23:22 ` Rafael J. Wysocki
2007-05-11 23:25 ` Andrew Morton
2007-05-12 0:16 ` Rafael J. Wysocki
2007-05-11 23:29 ` Linus Torvalds
2007-05-12 0:01 ` Rafael J. Wysocki
2007-05-12 8:16 ` Gautham R Shenoy
2007-05-12 9:27 ` Rafael J. Wysocki
2007-05-12 10:13 ` Gautham R Shenoy
2007-05-12 10:41 ` Rafael J. Wysocki
2007-05-12 10:52 ` Gautham R Shenoy
2007-05-12 11:34 ` Rafael J. Wysocki
2007-05-12 14:25 ` Oleg Nesterov
2007-05-12 14:59 ` migrate_dead_tasks() vs sleep-after-exit_notify() problems? Oleg Nesterov
2007-05-10 22:37 ` [PATCH 2/7] Freezer: Close potential race between refrigerator and thaw_tasks Rafael J. Wysocki
2007-05-10 22:38 ` [PATCH 3/7] Freezer: Fix vfork problem Rafael J. Wysocki
2007-05-10 22:39 ` [PATCH 4/7] Freezer: Take kernel_execve into consideration Rafael J. Wysocki
2007-05-10 22:41 ` [PATCH 5/7] Freezer: Fix kthread_create vs freezer theoretical race Rafael J. Wysocki
2007-05-10 22:43 ` [PATCH 6/7] Freezer: Fix PF_NOFREEZE vs freezeable race Rafael J. Wysocki
2007-05-10 22:44 ` [PATCH 7/7] Freezer: Move frozen_process to kernel/power/process.c Rafael J. Wysocki
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