On Tue, 2017-08-08 at 07:06:32 UTC, Michael Ellerman wrote: > In iommu_range_alloc() we generate a mask by right shifting ~0, > however if the specified alignment is 0 then we right shift by 64, > which is undefined. UBSAN tells us so: > > UBSAN: Undefined behaviour in ../arch/powerpc/kernel/iommu.c:193:35 > shift exponent 64 is too large for 64-bit type 'long unsigned int' > > We can avoid it by instead generating the mask with: > > align_mask = (1ull << align_order) - 1; > > That will also generate an undefined shift if align_order is 64 or > greater, but that shouldn't be a problem for a while. > > Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Applied to powerpc next. https://git.kernel.org/powerpc/c/63b85621d9aa6bdc410f01b22f7821 cheers
