Messages in this thread | | | Subject | Re: [discuss] Re: [PATCH] [3/4] i386: Fix overflow in e820_all_mapped | From | Arjan van de Ven <> | Date | Fri, 28 Apr 2006 09:34:02 +0200 |
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On Fri, 2006-04-28 at 09:07 +0200, Jan Beulich wrote: > >>> Linus Torvalds <torvalds@osdl.org> 28.04.06 07:39 >>> > > > > > >On Fri, 28 Apr 2006, Andi Kleen wrote: > >> > >> The 32bit version of e820_all_mapped() needs to use u64 to avoid > >> overflows on PAE systems. Pointed out by Jan Beulich > > > >I don't think that's true. > > > >It can't be called with 64-bit arguments anyway. If the base address > >doesn't fit in 32-bit, we'd be screwed in other places, afaik. > > The arguments don't necessarily need to be u64, but (at least some of) > the calculations inside the function do. Otherwise, a region starting > below 4G and extending to or beyond 4G would not be considered > correctly.
since this is use-once __init code I rather keep it simple and safe (eg use u64) than do complex tricks to make it safe in another way.. and the 4G thing is a real potential problem that's easily fixed with the u64 thing.
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