Re: Memory corruption due to word sharing

From: DJ Delorie
Date: Fri Feb 03 2012 - 01:46:34 EST

Jan Kara <jack@xxxxxxx> writes:
> we've spotted the following mismatch between what kernel folks expect
> from a compiler and what GCC really does, resulting in memory corruption on
> some architectures. Consider the following structure:
> struct x {
> long a;
> unsigned int b1;
> unsigned int b2:1;
> };

If this structure were volatile, you could try
-fstrict-volatile-bitfields, which forces GCC to use the C type to
define the access width, instead of doing whatever it thinks is optimal.

Note: that flag is enabled by default for some targets already, most
notably ARM.
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