Il 02/09/2014 18:13, Laurent Dufour ha scritto: > fc95ca7284bc54953165cba76c3228bd2cdb9591 introduces a memset in > kvmppc_alloc_hpt since the general CMA doesn't clear the memory it > allocates. > > However, the size argument passed to memset is computed from a signed value > and its signed bit is extended by the cast the compiler is doing. This lead > to extremely large size value when dealing with order value >= 31, and > almost all the memory following the allocated space is cleaned. As a > consequence, the system is panicing and may even fail spawning the kdump > kernel. > > This fix makes use of an unsigned value for the memset's size argument to > avoid sign extension. Among this fix, another shift operation which may > lead to signed extended value too is also fixed. > > Cc: Alexey Kardashevskiy <[email protected]> > Cc: Paul Mackerras <[email protected]> > Cc: Alexander Graf <[email protected]> > Cc: Aneesh Kumar K.V <[email protected]> > Cc: Joonsoo Kim <[email protected]> > Cc: Benjamin Herrenschmidt <[email protected]> > Signed-off-by: Laurent Dufour <[email protected]> > --- > arch/powerpc/kvm/book3s_64_mmu_hv.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c > b/arch/powerpc/kvm/book3s_64_mmu_hv.c > index 72c20bb16d26..79294c4c5015 100644 > --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c > +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c > @@ -62,10 +62,10 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp) > } > > kvm->arch.hpt_cma_alloc = 0; > - page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT)); > + page = kvm_alloc_hpt(1ul << (order - PAGE_SHIFT)); > if (page) { > hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page)); > - memset((void *)hpt, 0, (1 << order)); > + memset((void *)hpt, 0, (1ul << order)); > kvm->arch.hpt_cma_alloc = 1; > } > >
Thanks, applied to kvm/master. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
