Memory corruption due to word sharing

[David Miller]

From: Michael Matz <matz@suse.de>
Date: Wed, 1 Feb 2012 18:41:05 +0100 (CET)

> One problem is that it's not a new problem, GCC emitted similar code since 
> about forever, and still they turned up only now (well, probably because 
> ia64 is dead, but sparc64 should have similar problems). 

Indeed, on sparc64 it does do the silly 64-bit access too:

wrong:
        ldx     [%o0+8], %g2
        sethi   %hi(2147483648), %g1
        or      %g2, %g1, %g1
        jmp     %o7+8
         stx    %g1, [%o0+8]

Personally I've avoided C bitfields like the plague in any code I've
written.