syscall_get_return_value
unsigned long error = syscall_get_return_value(task, regs);
trace_sys_exit(regs, syscall_get_return_value(current, regs));
trace_sys_exit(regs, syscall_get_return_value(current, regs));
long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs);
trace_syscall_exit(regs, syscall_get_return_value(current, regs));
info->exit.rval = syscall_get_return_value(child, regs);
rec->ret = syscall_get_return_value(current, regs);
entry->ret = syscall_get_return_value(current, regs);