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From: William Lee Irwin III <wli@holomorphy.com>
To: Pete Zaitcev <zaitcev@redhat.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: interrupt checks for spinlocks
Date: Sun, 3 Nov 2002 16:53:39 -0800	[thread overview]
Message-ID: <20021104005339.GA16347@holomorphy.com> (raw)
In-Reply-To: <20021103194249.A1603@devserv.devel.redhat.com>

From: William Lee Irwin III <wli@holomorphy.com>
>>>> (1) check that spinlocks are not taken in interrupt context without
>>>> 	interrupts disabled

At some point in the past, Pete Zaitcev wrote:
>>> Bill, why is this bad? I routinely use this technique.

From: William Lee Irwin III <wli@holomorphy.com>
>> If you receive the same interrupt on the same cpu and re-enter code
>> that does that, you will deadlock.

On Sun, Nov 03, 2002 at 07:42:49PM -0500, Pete Zaitcev wrote:
> How would that happen? I thought it was not possible to re-enter
> an interrupt, and that it was pretty fundamental for Linux.
> When did we allow it, and what are implications for architectures?

This non-reentrant stuff hurts my head. Another patch down the
toilet, I guess.


Bill

  reply	other threads:[~2002-11-04  0:48 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.1036362421.16883.linux-kernel2news@redhat.com>
     [not found] ` <200211040028.gA40S8600593@devserv.devel.redhat.com>
     [not found]   ` <20021104002813.GZ16347@holomorphy.com>
2002-11-04  0:42     ` interrupt checks for spinlocks Pete Zaitcev
2002-11-04  0:53       ` William Lee Irwin III [this message]
2002-11-04  1:18         ` Robert Love
2002-11-04  1:42           ` William Lee Irwin III
2002-11-04  3:01             ` Robert Love
2002-11-04  3:04               ` William Lee Irwin III
2002-11-04  3:22               ` William Lee Irwin III
2002-11-04  3:36               ` Zwane Mwaikambo
2002-11-03 22:08 William Lee Irwin III
2002-11-04  0:15 ` Davide Libenzi
2002-11-04  0:39   ` William Lee Irwin III
2002-11-04  1:39     ` Davide Libenzi
2002-11-04  1:39       ` William Lee Irwin III
2002-11-04  5:18       ` Randy.Dunlap
2002-11-04 15:47         ` Davide Libenzi
2002-11-04 13:31     ` Alan Cox

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