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; } -- 1.9.1 -- 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/
