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Date: Mon, 18 Aug 2008 21:06:57 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Huang Ying <ying.huang@intel.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATH -mm] Fix a race condtion of oops_in_progress
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On Mon, 18 Aug 2008 10:03:27 +0800 Huang Ying <ying.huang@intel.com> wrote:

> This patch fix a race condition of oops_in_progress. Which may be
> changed on multiple CPU simultaneously, but it is changed via
> non-atomic operation ++/--. This patch changes the definition of
> oops_in_process from int to atomic_t, and accessing method to atomic
> operations.


> extern atomic_t oops_in_progress;

In file included from include/asm/system.h:10,
                 from include/asm/processor.h:17,
                 from include/asm/atomic_32.h:5,
                 from include/asm/atomic.h:2,
                 from include/linux/crypto.h:20,
                 from arch/x86/kernel/asm-offsets_32.c:7,
                 from arch/x86/kernel/asm-offsets.c:2:
include/linux/kernel.h:236: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'oops_in_progress'
make[1]: *** [arch/x86/kernel/asm-offsets.s] Error 1
make: *** [prepare0] Error 2

we can't inlude asm/atomic.h from linux/kernel.h because asm/atomic.h
includes linux/kernel.h via the above route.

And we cannot forward-declare atomic_t by hand because it's a typedef.

Not sure what to do, really.  Find a different header file in which to
declare oops_in_progress?