From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>, Ingo Molnar <mingo@elte.hu>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ming Lei <tom.leiming@gmail.com>
Subject: Re: [PATCH 2/2] lockdep: Don't only check recursive read locks once in a sequence
Date: Thu, 19 Nov 2009 18:13:48 +0100 [thread overview]
Message-ID: <1258650828.3931.437.camel@laptop> (raw)
In-Reply-To: <20091119155549.GB4967@nowhere>
On Thu, 2009-11-19 at 16:55 +0100, Frederic Weisbecker wrote:
> And btw I
> don't understand why rwsem read locks are not considered as
> recursive in lockdep.
Because they're not.
rwsems are FIFO fair, so a double read can deadlock when there's a
pending writer inbetween.
next prev parent reply other threads:[~2009-11-19 17:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-18 1:06 [PATCH 0/2] lockdep: Improvements for rwlocks dependency inversion detection Frederic Weisbecker
2009-11-18 1:06 ` [PATCH 1/2] lockdep: Include recursive read-locks dependencies in the tree Frederic Weisbecker
2009-11-18 10:26 ` Peter Zijlstra
2009-11-19 16:07 ` Frederic Weisbecker
2009-11-18 1:06 ` [PATCH 2/2] lockdep: Don't only check recursive read locks once in a sequence Frederic Weisbecker
2009-11-18 9:43 ` Lai Jiangshan
2009-11-19 15:55 ` Frederic Weisbecker
2009-11-19 17:13 ` Peter Zijlstra [this message]
2009-11-20 0:57 ` Frederic Weisbecker
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