Date: Mon, 18 Aug 2008 09:42:21 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com,
       Alexander Viro <viro@ftp.linux.org.uk>
Subject: Re: [PATCH] lockdep: fix spurious 'inconsistent lock state' warning
Message-ID: <20080818074221.GD30694@elte.hu>
References: <1219019197-17744-1-git-send-email-dbaryshkov@gmail.com>
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* Dmitry Baryshkov <dbaryshkov@gmail.com> wrote:

> Since f82b217e3513fe3af342c0f3ee1494e86250c21c lockdep can output 
> spurious warnings related to hwirqs due to hardirq_off shrinkage from 
> int to bit-sized flag. Guard it with double negation to fix the 
> warning.
> 
> Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>

good spotting! Applied to tip/core/urgent, thanks Dmitry.

I'm wondering, is there any way to teach gcc some sanity here - a safer 
variant of bitfields, that is just not allowed to overflow into or 
corrupt nearby fields? The fact that a benign looking hlock->state = 15 
can corrupt other fields worries me quite a bit. Valid C semantics or 
not, this is a totally dangerous construct. The space savings are very 
real though, so it would be nice to get 'safer bitfields', somehow.

	Ingo
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