Memory corruption due to word sharing

[Colin Walters]

On Wed, 2012-02-01 at 16:19 +0100, Jan Kara wrote:

> I've raised the issue with our GCC guys and they said to me that: "C does
> not provide such guarantee, nor can you reliably lock different
> structure fields with different locks if they share naturally aligned
> word-size memory regions.  The C++11 memory model would guarantee this,
> but that's not implemented nor do you build the kernel with a C++11
> compiler."

That's interesting.  So it seems like there are two solutions:

1) Use the same lock for a given bitfield
2) Split up the bitfield into different words