Messages in this thread | | | Subject | Re: [PATCH] core: Catch overflows in do_div() function | From | Joe Perches <> | Date | Tue, 08 Oct 2013 09:51:20 -0700 |
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On Tue, 2013-10-08 at 18:45 +0200, Richard Weinberger wrote: > On Tue, Oct 8, 2013 at 6:18 PM, Joe Perches <joe@perches.com> wrote: > > On Tue, 2013-10-08 at 09:10 -0700, Anatol Pomozov wrote: > >> If second parameter passed to this function was 64 then it silently > >> truncates to 32 bits. Catch such situation. > > [] > >> diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h > > [] > >> @@ -25,6 +26,7 @@ > >> # define do_div(n,base) ({ \ > >> uint32_t __base = (base); \ > >> uint32_t __rem; \ > >> + BUG_ON(sizeof(base) > 4 && base >= (1UL<<32)); \ > > > > I think this would be better as a BUILD_BUG_ON > > No. BUILD_BUG_ON works only for constants.
Add __builtin_constant_p(base).
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