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From: David Miller <davem@davemloft.net>
To: rostedt@goodmis.org
Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, kaber@trash.net, mingo@elte.hu,
	peterz@infradead.org
Subject: Re: [LOCKDEP BUG][2.6.36-rc1] xt_info_wrlock?
Date: Mon, 16 Aug 2010 12:44:00 -0700 (PDT)	[thread overview]
Message-ID: <20100816.124400.42792595.davem@davemloft.net> (raw)
In-Reply-To: <1281981301.3268.110.camel@gandalf.stny.rr.com>

From: Steven Rostedt <rostedt@goodmis.org>
Date: Mon, 16 Aug 2010 13:55:01 -0400

> Please tell me what prevents an interrupt going off after we grab the
> xt_info_wrlock(cpu) in get_counters().

He's only accessing the per-cpu counter locks of other cpus.

The per-cpu lock is only locally accessed by a cpu in software
interrupt context.

That is why his transformation is legal.

Lockdep simply hasn't been informed of this invariant and has
to assume the worst.

  parent reply	other threads:[~2010-08-16 19:44 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-16 17:07 [LOCKDEP BUG][2.6.36-rc1] xt_info_wrlock? Steven Rostedt
2010-08-16 17:31 ` Eric Dumazet
2010-08-16 17:55   ` Steven Rostedt
2010-08-16 18:16     ` Steven Rostedt
2010-08-16 18:36       ` Peter Zijlstra
2010-08-16 18:48         ` Eric Dumazet
2010-08-16 19:16           ` Peter Zijlstra
2010-08-16 19:35             ` Eric Dumazet
2010-08-16 20:01               ` Peter Zijlstra
2010-08-16 20:17                 ` Eric Dumazet
2010-08-16 18:48       ` Eric Dumazet
2010-08-16 19:44     ` David Miller [this message]
2010-08-16 20:04       ` Peter Zijlstra

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