Re: [PATCH v2] x86/xen: Add some null pointer checking to smp.c

[Kunwu Chan]

On 2024/1/17 18:40, Markus Elfring wrote:
> > kasprintf() returns a pointer to dynamically allocated memory
> > which can be NULL upon failure. Ensure the allocation was successful
> > by checking the pointer validity.
> …
> > +++ b/arch/x86/xen/smp.c
> > @@ -61,10 +61,14 @@ void xen_smp_intr_free(unsigned int cpu)
> >
> >   int xen_smp_intr_init(unsigned int cpu)
> >   {
> > -	int rc;
> > +	int rc = 0;
>
> I find the indication of a successful function execution sufficient by
> the statement “return 0;” at the end.
> How do you think about to omit such an extra variable initialisation?
Thanks, it's no need now. I'll remove it in v3.
> >   	char *resched_name, *callfunc_name, *debug_name;
> >
> >   	resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
> > +	if (!resched_name) {
> > +		rc = -ENOMEM;
> > +		goto fail;
> > +	}
> >   	per_cpu(xen_resched_irq, cpu).name = resched_name;
> >   	rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
> >   				    cpu,
>
> You propose to apply the same error code in four if branches.
> I suggest to avoid the specification of duplicate assignment statements
> for this purpose.
> How do you think about to use another label like “e_nomem”?
I'll add a new label to simply the code.
> Regards,
> Markus
--
Thanks,
  Kunwu