Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Thu, 18 Nov 2021 14:14:54 +0100 | Subject | Re: [PATCH] cpufreq: intel_pstate: Avoid using CPPC when ACPI CPC is not valid |
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On Thu, Nov 18, 2021 at 1:46 PM Kai-Heng Feng <kai.heng.feng@canonical.com> wrote: > > If ACPI CPC is not valid, dereference cpc_desc in cppc_get_perf() causes > a NULL pointer dereference. So avoid using CPPC for that scenario. > > Fixes: 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP calibration") > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
The bug is real, but it is not in intel_pstate.
cppc_get_perf() should return an error in that case.
Let me fix this.
> --- > drivers/cpufreq/intel_pstate.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 815df3daae9df..24c7d705b99b6 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -3369,7 +3369,7 @@ static int __init intel_pstate_init(void) > if (!default_driver) > default_driver = &intel_pstate; > > - if (boot_cpu_has(X86_FEATURE_HYBRID_CPU)) > + if (boot_cpu_has(X86_FEATURE_HYBRID_CPU) && acpi_cpc_valid()) > intel_pstate_cppc_set_cpu_scaling(); > > goto hwp_cpu_matched; > -- > 2.32.0 >
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