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

[Kunwu Chan <chentao@xxxxxxxxxx>]

On 2024/1/22 16:30, Dan Carpenter wrote:
> On Fri, Jan 19, 2024 at 05:22:25PM +0800, Kunwu Chan wrote:
> > 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.
> This advice is good.  Don't do unnecessary assignments.
Thanks for your suggestions, I'll keep it in mind.
> > > >         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.
> I'm not a Xen maintainer so I can't really comment on their style
> choices.  However, as one of the kernel-janitors list people, I would
> say that not everyone agrees with Markus's style preferences.  Markus
> was banned from the list for a while, but we unbanned everyone when we
> transitioned to the new list infrastructure.  Do a search on lore to
> find out more.  https://lore.kernel.org/all/?q=Elfring
>
> Perhaps wait for feedback from the maintainers for how to proceed?
OK, I'll wait for the feedback.
> regards,
> dan carpenter
--
Thanks,
  Kunwu