> > +#ifdef CONFIG_X86_FRED > > +static bool ex_handler_eretu(const struct exception_table_entry *fixup, > > + struct pt_regs *regs, unsigned long > > +error_code) { > > + struct pt_regs *uregs = (struct pt_regs *)(regs->sp - offsetof(struct pt_regs, > ip)); > > + unsigned short ss = uregs->ss; > > + unsigned short cs = uregs->cs; > > + > > + fred_info(uregs)->edata = fred_event_data(regs); > > + uregs->ssx = regs->ssx; > > + uregs->ss = ss; > > + uregs->csx = regs->csx; > > + uregs->current_stack_level = 0; > > + uregs->cs = cs; > > Hello > > If the ERETU instruction had tried to return from NMI to ring3 and just faulted, is > NMI still blocked? Do you mean the NMI FRED stack frame contains an invalid ring3 context?