Re: [PATCH v3 4/5] bug: Provide toggle for BUG on data corruption

Arnd Bergmann
2016-08-22T13:17:07Z

On Wednesday, August 17, 2016 2:42:11 PM CEST Kees Cook wrote:
> +
> +/*
> + * Since detected data corruption should stop operation on the affected
> + * structures, this returns false if the corruption condition is found.
> + */
> +#define CHECK_DATA_CORRUPTION(condition, fmt, ...) \
> + do { \
> + if (unlikely(condition)) { \
> + if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \
> + pr_err(fmt, ##__VA_ARGS__); \
> + BUG(); \
> + } else \
> + WARN(1, fmt, ##__VA_ARGS__); \
> + return false; \
> + } \
> + } while (0)
> +

I think the "return false" inside of the macro makes it easy to misread
what is actually going on.

How about making it a macro that returns the condition argument?

#define CHECK_DATA_CORRUPTION(condition, fmt, ...) \
({ \
bool _condition = unlikely(condition); \
if (_condition) { \
...
} \
_condition; \
})

Arnd