From: Linus Torvalds <torvalds@osdl.org>
To: Andrew Volkov <Andrew.Volkov@transas.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: PROBLEM: possible proceses leak
Date: Mon, 8 Dec 2003 11:08:27 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.58.0312081106150.13236@home.osdl.org> (raw)
In-Reply-To: <2E74F312D6980D459F3A05492BA40F8D0391B0E9@clue.transas.com>
On Mon, 8 Dec 2003, Andrew Volkov wrote:
>
> In all kernels (up to 2.6-test11) next sequence of code
> in __down/__down_interruptible function
> (arch/i386/kernel/semaphore.c) may cause processes or threads leaking.
Nope. Quite the reverse, in fact. Having the "state" setting above the
wait-queue is usually a good idea, since it means that there are less
races to worry about.
> |-----tsk->state = TASK_UNINTERRUPTIBLE; <----- BUG:
> | -- If "do_schedule" from kernel/schedule will calling
> | at this point, due to expire of time slice,
> | then current task will removed from run_queue,
> | but doesn't added to any waiting queue, and hence
> | will never run again. --
No.
Kernel preemption is special, and it will preempt the process WITHOUT
CHANGING the state of it. See the PREEMPT_ACTIVE test in schedule(). The
process will still be left on the run-queue, and it will be run again,
even if it is marked sleeping.
Linus
next prev parent reply other threads:[~2003-12-08 19:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-08 18:01 PROBLEM: possible proceses leak Andrew Volkov
2003-12-08 18:25 ` William Lee Irwin III
2003-12-08 19:08 ` Linus Torvalds [this message]
2003-12-08 18:45 Andrew Volkov
2003-12-08 18:51 ` William Lee Irwin III
2003-12-08 19:09 ` Linus Torvalds
2003-12-08 19:23 ` William Lee Irwin III
2003-12-08 19:34 Andrew Volkov
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