From: Xiaomeng Tong xiam0nd.tong@gmail.com
commit 300981abddcb13f8f06ad58f52358b53a8096775 upstream.
The bug is here: if (!p) return ret;
The list iterator value 'p' will *always* be set and non-NULL by list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty or no element is found.
To fix the bug, Use a new value 'iter' as the list iterator, while use the old value 'p' as a dedicated variable to point to the found element.
Fixes: dfaa973ae960 ("KVM: PPC: Book3S HV: In H_SVM_INIT_DONE, migrate remaining normal-GFNs to secure-GFNs") Cc: stable@vger.kernel.org # v5.9+ Signed-off-by: Xiaomeng Tong xiam0nd.tong@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20220414062103.8153-1-xiam0nd.tong@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/kvm/book3s_hv_uvmem.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -360,13 +360,15 @@ static bool kvmppc_gfn_is_uvmem_pfn(unsi static bool kvmppc_next_nontransitioned_gfn(const struct kvm_memory_slot *memslot, struct kvm *kvm, unsigned long *gfn) { - struct kvmppc_uvmem_slot *p; + struct kvmppc_uvmem_slot *p = NULL, *iter; bool ret = false; unsigned long i;
- list_for_each_entry(p, &kvm->arch.uvmem_pfns, list) - if (*gfn >= p->base_pfn && *gfn < p->base_pfn + p->nr_pfns) + list_for_each_entry(iter, &kvm->arch.uvmem_pfns, list) + if (*gfn >= iter->base_pfn && *gfn < iter->base_pfn + iter->nr_pfns) { + p = iter; break; + } if (!p) return ret; /*