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Message-ID: <cb62342b04110103057dc7dff0@mail.gmail.com>
Date: Mon, 1 Nov 2004 12:05:04 +0100
From: Carlos Vidal <yorugua@gmail.com>
Reply-To: carlos@tarkus.se
To: linux-kernel@vger.kernel.org
Subject: spinlock_t typedef visibility and uninitialized spinlock
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I'm porting CIPE 1.6.0 kernel module to Kernel 2.6.8 and had problems
with "spin_is_locked on uninitialized spinlock".

After tracing the problem I found that the spinlock_t structure is not
visible to the module code. A 'gcc -E' yields:
     typedef struct { } spinlock_t;

In spinlock.h, this declaration is inside a #ifdef
CONFIG_DEBUG_SPINLOCK block, so it becomes visible only
CONFIG_DEBUG_SPINLOCK is 'y'.

If I turn CONFIG_DEBUG_SPINLOCK on, the module loads nicely. Otherwise
I get a nasty error in syslog and sometimes a system crash, as if in
CIPE the struct was not allocated (what is the case if the compiler
uses the typedef as it is above).

The question is: is this a bug or a feature? ;-)

Should the declaration be out of the #ifdef CONFIG_DEBUG_SPINLOCK? Or
should I use a special compiler flag?

Carlos
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