Hi Zefan, Suresh or Peter, 9c1c3fac53378c9782c18f80107965578d7b7167 x86, kvm: use kernel_fpu_begin/end() in kvm_load/put_guest_fpu() We never cause the "Device Not Available" exception in kernel mode, but without this patch, the orign unlazy_fpu() do stts(), the following fpu_restore_checking() will trigger a DNA(Device Not Available), this may corrupt the user process fpu. And an crash happened through a fault injection in our scenario. b1a74bf8212367be2b1d6685c11a84e056eaaaf1 x86, kvm: fix kvm's usage of kernel_fpu_begin/end() The commit b1a74bf82123 fix a bug introduced by comit 9c1c3fac5337 (x86, kvm: use kernel_fpu_begin/end() in kvm_load/put_guest_fpu()) They look applicable to stable-3.4.y. The first one can be applied cleanly, the other need some adjustments to backport. The following patche is the backport for b1a74bf82123. And what do you think? Thanks. -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html