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authorLaurent Dufour <ldufour@linux.vnet.ibm.com>2014-09-02 18:13:01 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2014-09-03 10:34:07 +0200
commit02a68d0503fa470abff8852e10b1890df5730a08 (patch)
tree19b8bd2d73b03d5a24bc0d1eb0043c266d710b53
parenteebbcf6da9874db62bce4c9000e688985ff23f68 (diff)
powerpc/kvm/cma: Fix panic introduces by signed shift operation
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 <aik@ozlabs.ru> Cc: Paul Mackerras <paulus@samba.org> Cc: Alexander Graf <agraf@suse.de> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/powerpc/kvm/book3s_64_mmu_hv.c4
1 files 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;
}