On Fri, Dec 12 2014, Mark Brown <broo...@kernel.org> wrote: > On Tue, Dec 09, 2014 at 10:53:41PM +0100, Rasmus Villemoes wrote: > >> if (a->reg != b->reg) >> return a->reg - b->reg; >> - if (a->dapm != b->dapm) >> - return (unsigned long)a->dapm - (unsigned long)b->dapm; >> + if (a->dapm < b->dapm) >> + return -1; >> + if (a->dapm > b->dapm) >> + return 1; > > If we're worrying about standards conformance type stuff here this is > also buggy since it's out of spec to compare pointers that are not part > of the same array like this. Casting to uintptr_t is a better fix here.
I'm not worrying about standards conformance. Casting pointers to and from [unsigned] long is done everywhere in the kernel, and that's fine. But subtracting ints or longs and using the sign of the result for comparison is simply wrong. See acbbe6fbb2 (kcmp: fix standard comparison bug) for the long story. In this case the narrowing (when BITS_PER_LONG==64) of the result from long to int just makes it even more wrong. Rasmus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
