On 17.04.2025 12:30, Ross Lagerwall wrote:
> --- a/xen/drivers/acpi/pmstat.c
> +++ b/xen/drivers/acpi/pmstat.c
> @@ -104,6 +104,14 @@ int do_get_pm_info(struct xen_sysctl_get_pmstat *op)
> cpufreq_residency_update(op->cpuid, pxpt->u.cur);
>
> ct = pmpt->perf.state_count;
> +
> + if ( op->u.getpx.total < ct )
> + {
> + spin_unlock(cpufreq_statistic_lock);
> + ret = -ENOSPC;
> + break;
> + }
Simply producing an error is not an option imo. See pmstat_get_cx_stat()'s
behavior. Imo the calculation of ct wants to become
ct = min(pmpt->perf.state_count, op->u.getpx.total);
yet then the copying of the 2-dim array of data becomes more complicated
when ct < pmpt->perf.state_count. An option may be to document that this
array is copied only when the buffer is large enough.
Furthermore I think it would be a good idea to also amend the public header
with IN/OUT annotations for the fields which are input and output (also for
the Cx part, ideally).
And then - doesn't xc_pm_get_pxstat() have a similar issue?
Jan
