From: Pavel Machek <pavel@ucw.cz>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Andrew Morton <akpm@osdl.org>,
LKML <linux-kernel@vger.kernel.org>,
Oleg Nesterov <oleg@tv-sign.ru>,
Aneesh Kumar <aneesh.kumar@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Gautham R Shenoy <ego@in.ibm.com>
Subject: Re: [PATCH -mm 2/7] Freezer: Close theoretical race between refrigerator and thaw_tasks
Date: Thu, 1 Mar 2007 16:39:08 +0000 [thread overview]
Message-ID: <20070301163907.GA4710@ucw.cz> (raw)
In-Reply-To: <200703011608.13758.rjw@sisk.pl>
On Thu 2007-03-01 16:08:12, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
>
> If the freezing of tasks fails and a task is preempted in refrigerator() before
> calling frozen_process(), then thaw_tasks() may run before this task is frozen.
> In that case the task will freeze and no one will thaw it.
>
> To fix this race we can call freezing(current) in refrigerator() along with
> frozen_process(current) under the task_lock() which also should be taken in
> the error path of try_to_freeze_tasks() as well as in thaw_process(). Moreover,
> if thaw_process() additionally clears TIF_FREEZE for tasks that are not frozen,
> we can be sure that all tasks are thawed and there are no pending "freeze"
> requests after thaw_tasks() has run.
>
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
ack.
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2007-03-01 16:39 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-26 7:00 [PATCH -mm 0/6] Freezer changes Rafael J. Wysocki
2007-02-26 7:02 ` [PATCH -mm 1/6] Freezer: Read PF_BORROWED_MM in a nonracy way Rafael J. Wysocki
2007-02-26 7:05 ` [PATCH -mm 2/6] Freezer: Fix memory ordering in refrigerator Rafael J. Wysocki
2007-02-26 11:32 ` Oleg Nesterov
2007-02-26 7:06 ` [PATCH -mm 3/6] Freezer: Close theoretical race between refrigerator and thaw_tasks Rafael J. Wysocki
2007-02-26 7:08 ` [PATCH -mm 4/6] Freezer: Remove PF_NOFREEZE from rcutorture thread Rafael J. Wysocki
2007-02-26 7:11 ` [PATCH -mm 5/6] Freezer: Remove PF_NOFREEZE from bluetooth threads Rafael J. Wysocki
2007-02-26 7:13 ` [PATCH -mm 6/6] Freezer: Add try_to_freeze calls to all kernel threads Rafael J. Wysocki
2007-03-01 15:05 ` [PATCH -mm 0/7] Freezer changes (take 2) Rafael J. Wysocki
2007-03-01 15:06 ` [PATCH -mm 1/7] Freezer: Read PF_BORROWED_MM in a nonracy way Rafael J. Wysocki
2007-03-01 15:08 ` [PATCH -mm 2/7] Freezer: Close theoretical race between refrigerator and thaw_tasks Rafael J. Wysocki
2007-03-01 16:39 ` Pavel Machek [this message]
2007-03-01 15:09 ` [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread Rafael J. Wysocki
2007-03-01 19:38 ` Anton Blanchard
2007-03-01 19:54 ` Rafael J. Wysocki
2007-03-02 21:35 ` Paul E. McKenney
2007-03-02 22:16 ` Anton Blanchard
2007-03-02 23:33 ` Oleg Nesterov
2007-03-03 0:58 ` Paul E. McKenney
2007-03-03 17:32 ` Oleg Nesterov
2007-03-04 4:34 ` Srivatsa Vaddagiri
2007-03-11 17:49 ` [PATCH] kthread_should_stop_check_freeze (was: Re: [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread) Rafael J. Wysocki
2007-03-12 4:38 ` Paul E. McKenney
2007-03-12 8:14 ` Pavel Machek
2007-03-12 11:19 ` Rafael J. Wysocki
2007-03-12 12:23 ` Oleg Nesterov
2007-03-12 13:24 ` [PATCH] kthread_should_stop_check_freeze Cedric Le Goater
2007-03-12 18:25 ` Rafael J. Wysocki
2007-03-12 22:39 ` [PATCH] kthread_should_stop_check_freeze (was: Re: [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread) Pavel Machek
2007-03-12 22:45 ` Anton Blanchard
2007-03-13 3:14 ` Srivatsa Vaddagiri
2007-03-13 9:16 ` Christoph Hellwig
2007-03-13 9:58 ` Srivatsa Vaddagiri
2007-03-13 10:20 ` Christoph Hellwig
2007-03-20 18:08 ` Pavel Machek
2007-03-13 0:58 ` Paul E. McKenney
2007-03-20 18:10 ` Pavel Machek
2007-03-13 5:27 ` Gautham R Shenoy
2007-03-13 5:42 ` Srivatsa Vaddagiri
2007-03-03 1:03 ` [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread Rafael J. Wysocki
2007-03-02 6:57 ` Gautham R Shenoy
2007-03-02 21:46 ` Paul E. McKenney
2007-03-01 15:10 ` [PATCH -mm 4/7] Freezer: Remove PF_NOFREEZE from bluetooth threads Rafael J. Wysocki
2007-03-01 15:12 ` [PATCH -mm 5/7] Freezer: Add try_to_freeze calls to all kernel threads Rafael J. Wysocki
2007-03-01 15:15 ` [PATCH -mm 6/7] Freezer: Fix vfork problem Rafael J. Wysocki
2007-03-01 15:17 ` [PATCH -mm 7/7] Freezer: Take kernel_execve into consideration Rafael J. Wysocki
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