Messages in this thread | | | Date | Thu, 30 Mar 2023 01:39:18 +0000 | From | "Yajun Deng" <> | Subject | Re: [PATCH] cpufreq: Fix policy->freq_table is NULL in __cpufreq_driver_target() |
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March 29, 2023 10:21 PM, "Rafael J. Wysocki" <rafael@kernel.org> wrote:
> On Wed, Mar 29, 2023 at 3:36 PM Yajun Deng <yajun.deng@linux.dev> wrote: > >> __resolve_freq() may be return target_freq if policy->freq_table is >> NULL. In this case, it should return -EINVAL before __target_index(). > > Even so, __target_index() itself doesn't dereference freq_table > AFAICS, so arguably the driver should be prepared to deal with a NULL > freq_table which comes from it after all. >
But there is a statement 'unsigned int newfreq = policy->freq_table[index].frequency;' in __target_index(), if driver doesn't provide freq_table, __target_index() will fault before the driver itself.
> Or, if you want to argue that drivers providing ->target_index() must > also provide freq_table that is not NULL, a check to that effect needs > to be done at the driver registration time IMO. > >> Signed-off-by: Yajun Deng <yajun.deng@linux.dev> >> --- >> drivers/cpufreq/cpufreq.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c >> index c0e5be0fe2d6..308a3df1a940 100644 >> --- a/drivers/cpufreq/cpufreq.c >> +++ b/drivers/cpufreq/cpufreq.c >> @@ -2299,7 +2299,7 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy, >> return cpufreq_driver->target(policy, target_freq, relation); >> } >> >> - if (!cpufreq_driver->target_index) >> + if (!cpufreq_driver->target_index || !policy->freq_table) >> return -EINVAL; >> >> return __target_index(policy, policy->cached_resolved_idx); >> --
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