From: Christian Borntraeger Date: Wed, 6 Aug 2014 14:17:58 +0000 (+0200) Subject: KVM: s390: Fix user triggerable bug in dead code X-Git-Tag: v3.16.4~150 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8966cb2bab57936a01e75df15b49f8a469aca58d;p=thirdparty%2Fkernel%2Fstable.git KVM: s390: Fix user triggerable bug in dead code commit 614a80e474b227cace52fd6e3c790554db8a396e upstream. In the early days, we had some special handling for the KVM_EXIT_S390_SIEIC exit, but this was gone in 2009 with commit d7b0b5eb3000 (KVM: s390: Make psw available on all exits, not just a subset). Now this switch statement is just a sanity check for userspace not messing with the kvm_run structure. Unfortunately, this allows userspace to trigger a kernel BUG. Let's just remove this switch statement. Signed-off-by: Christian Borntraeger Reviewed-by: Cornelia Huck Reviewed-by: David Hildenbrand Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 2f3e14fe91a48..0eaf87281f457 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1286,19 +1286,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) kvm_s390_vcpu_start(vcpu); - switch (kvm_run->exit_reason) { - case KVM_EXIT_S390_SIEIC: - case KVM_EXIT_UNKNOWN: - case KVM_EXIT_INTR: - case KVM_EXIT_S390_RESET: - case KVM_EXIT_S390_UCONTROL: - case KVM_EXIT_S390_TSCH: - case KVM_EXIT_DEBUG: - break; - default: - BUG(); - } - vcpu->arch.sie_block->gpsw.mask = kvm_run->psw_mask; vcpu->arch.sie_block->gpsw.addr = kvm_run->psw_addr; if (kvm_run->kvm_dirty_regs & KVM_SYNC_PREFIX) {