Messages in this thread | | | Date | Mon, 3 Nov 2014 06:48:01 -0800 | From | Josh Triplett <> | Subject | Re: [PATCH] compiler: Correct macro parameter expansion problem |
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On Mon, Nov 03, 2014 at 06:34:13AM -0800, Jeff Kirsher wrote: > From: Mark Rustad <mark.d.rustad@intel.com> > > The macro __compiletime_error_fallback has an error in that it > lacks parens around the expansion of an expression. It also > lacks a conversion to a boolean value. The first problem can > result in a mis-evaluation. The second problem can also result > in an error if the value comes out negative. That would thwart > the intended error generation. That is, the error being asserted > would not in fact generate an error. Fix both problems by adding > !!() to the expansion. > > Signed-off-by: Mark Rustad <mark.d.rustad@intel.com> > Tested-by: Aaron Brown <aaron.f.brown@intel.com> > Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Good catch.
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
> include/linux/compiler.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > index d5ad7b1..59dc611 100644 > --- a/include/linux/compiler.h > +++ b/include/linux/compiler.h > @@ -331,7 +331,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); > */ > # ifndef __CHECKER__ > # define __compiletime_error_fallback(condition) \ > - do { ((void)sizeof(char[1 - 2 * condition])); } while (0) > + do { ((void)sizeof(char[1 - 2 * !!(condition)])); } while (0) > # endif > #endif > #ifndef __compiletime_error_fallback > -- > 1.9.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sparse" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
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