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From: David Woodhouse <dwmw2@infradead.org>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Alexander Viro <viro@math.psu.edu>,
	linux-kernel@vger.kernel.org,
	Dawson Engler <engler@csl.Stanford.EDU>
Subject: Re: [CHECKER] a couple potential deadlocks in 2.4.5-ac8
Date: Sat, 09 Jun 2001 20:33:01 +0100	[thread overview]
Message-ID: <19317.992115181@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.21.0106091148380.26187-100000@penguin.transmeta.com>
In-Reply-To: <Pine.LNX.4.21.0106091148380.26187-100000@penguin.transmeta.com>


torvalds@transmeta.com said:
>  Good point. Spinlocks (with the exception of read-read locks, of
> course) and semaphores will deadlock on recursive use, while the BKL
> has this "process usage counter" recursion protection.

Obtaining a read lock twice can deadlock too, can't it?

	A		B
	read_lock()
			write_lock()
			...sleeps...
	read_lock()
	...sleeps...

Or do we not make new readers sleep if there's a writer waiting?

--
dwmw2



  reply	other threads:[~2001-06-09 19:34 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-06-09  7:59 [CHECKER] a couple potential deadlocks in 2.4.5-ac8 Dawson Engler
2001-06-09  8:11 ` checker suggestion Albert D. Cahalan
2001-06-10  2:04   ` Dawson Engler
2001-06-09 10:45 ` [CHECKER] a couple potential deadlocks in 2.4.5-ac8 Alexander Viro
2001-06-09 17:32 ` Linus Torvalds
2001-06-09 17:45   ` Alexander Viro
2001-06-09 19:01     ` Linus Torvalds
2001-06-09 19:33       ` David Woodhouse [this message]
2001-06-09 20:37         ` Linus Torvalds
2001-06-10 11:53         ` Rusty Russell
2001-06-10 11:59           ` David Woodhouse
2001-06-09 19:36       ` Alexander Viro
2001-06-09 20:42         ` Linus Torvalds
2001-06-09 21:44           ` Alexander Viro
2001-06-10  2:28       ` Dawson Engler
2001-06-10  6:19         ` Linus Torvalds
2001-06-10  7:45           ` Dawson Engler

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