From: Yong Zhang <yong.zhang@windriver.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>, Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] IRQ: Fix oneshot irq race between irq_finalize_oneshot and handle_level_irq
Date: Thu, 11 Mar 2010 17:13:39 +0800 [thread overview]
Message-ID: <20100311091339.GD8389@windriver.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1003110927450.22855@localhost.localdomain>
On Thu, Mar 11, 2010 at 09:41:45AM +0100, Thomas Gleixner wrote:
> No, it is _NOT_ harmless. interrupt handlers are guaranteed _NOT_ to
> be reentered. That's why we check the INPROGRESS flag.
>
> And you totally miss the case which caused the disussion in the first
> place: When the thread finishes _before_ the hard irq handler on the
> other CPU has set IRQ_MASKED. So this patch solves nothing at all, it
> just makes stuff worse than it was.
>
> Here is the solution which solves the inconsistent lock state _AND_
> the reentrancy race.
>
> http://git.kernel.org/?p=linux/kernel/git/tip/linux-2.6-tip.git;a=commit;h=0b1adaa031a55e44f5dd942f234bf09d28e8a0d6
>
> The change log has a full explanation of the scenarios.
Yeah, I see. Thanks for your point.
It will smooth the concerns.
Thanks,
Yong
prev parent reply other threads:[~2010-03-11 9:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-08 23:57 [RFC][PATCH] IRQ: Fix oneshot irq race between irq_finalize_oneshot and handle_level_irq Lars-Peter Clausen
2010-03-09 7:58 ` Thomas Gleixner
2010-03-09 8:08 ` Yong Zhang
2010-03-09 16:59 ` Valdis.Kletnieks
2010-03-09 18:10 ` Thomas Gleixner
2010-03-09 22:48 ` Lars-Peter Clausen
2010-03-09 23:32 ` Thomas Gleixner
2010-03-09 23:22 ` Thomas Gleixner
2010-03-10 3:21 ` Yong Zhang
2010-03-10 7:56 ` Thomas Gleixner
2010-03-11 2:55 ` Yong Zhang
2010-03-11 8:41 ` Thomas Gleixner
2010-03-11 9:13 ` Yong Zhang [this message]
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