From: Oleg Nesterov <oleg@tv-sign.ru>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, mingo@elte.hu
Subject: Re: [patch 2/2] hrtimer
Date: Tue, 28 Mar 2006 03:55:30 +0400 [thread overview]
Message-ID: <20060327235530.GA7024@oleg> (raw)
In-Reply-To: <1143411016.5344.139.camel@localhost.localdomain>
I also think this is racy.
CPU_0 CPU_1
hrtimer_wakeup:
task = t->task;
t->task = NULL;
<--- INTERRUPT --->
task is woken by signal,
do_nanosleep() sees t->task == NULL,
returns without hrtimer_cancel(),
and __exits__.
<--- RESUME --->
wake_up_process(task);
Instead of exit(), 'task' can go to TASK_STOPPED or TASK_UNINTERRUPTIBLE
after return from do_nanosleep(), it will be awakened by hrtimer_wakeup()
unexpectedly.
Oleg.
next prev parent reply other threads:[~2006-03-27 20:58 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-25 12:46 [patch 0/2] hrtimer: generic sleeper infrastructure Thomas Gleixner
2006-03-25 12:46 ` [patch 1/2] hrtimer Thomas Gleixner
2006-03-25 12:46 ` [patch 2/2] hrtimer Thomas Gleixner
2006-03-26 2:32 ` Andrew Morton
2006-03-26 22:10 ` Thomas Gleixner
2006-03-27 23:55 ` Oleg Nesterov [this message]
2006-03-28 0:03 ` Roman Zippel
2006-03-28 8:29 ` Thomas Gleixner
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