irqdomain: Let irq_domain_mapping display hierarchical domains

Hello Marc Zyngier,

This is a semi-automatic email about new static checker warnings.

The patch fe17a42e704a: "irqdomain: Let irq_domain_mapping display hierarchical domains" from May 12, 2017, leads to the following Smatch complaint:

kernel/irq/irqdomain.c:772 virq_debug_show_one()
warn: variable dereferenced before check 'data' (see line 758)

kernel/irq/irqdomain.c
757 while (domain) {

   758			unsigned int irq = data->irq;
                                           ^^^^^^^^^

Dereference.

759 unsigned long hwirq = data->hwirq;
760 struct irq_chip *chip;
761 bool direct;
762
763 if (data = &desc->irq_data)
764 seq_printf(m, "%5d ", irq);
765 else
766 seq_printf(m, "%5d+ ", irq);
767 seq_printf(m, "0x%05lx ", hwirq);
768
769 chip = irq_data_get_irq_chip(data);
770 seq_printf(m, "%-15s ", (chip && chip->name) ? chip->name : "none");
771
772 seq_printf(m, data ? "0x%p " : " %p ",

                                      ^^^^

Too late to check.

   773				   irq_data_get_irq_chip_data(data));
   774	

regards,
dan carpenter

On Tue, 13 Jun 2017 22:32:52 +0300
Dan Carpenter <[email protected]> wrote:

Hi Dan,

This check is utter crap, and I should have nuked it when reworking that code. We're guaranteed that if "data" becomes NULL at the end of that loop, so will "domain". So the check is a leftover of... something.

I'll fix it in a subsequent patch, thanks a lot for the report.

	M.

Without deviation from the norm, progress is not possible.