Re: [PATCH] ACPI: processor: Avoid NULL pointer dereferences at init time

Viresh Kumar
2019-10-16T03:38:15Z

On 15-10-19, 19:35, Rafael J. Wysocki wrote:
> rom: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> If there are neither processor objects nor processor device objects
> in the ACPI tables, the per-CPU processors table will not be
> initialized and attempting to dereference pointers from there will
> cause the kernel to crash. This happens in acpi_processor_ppc_init()
> and acpi_thermal_cpufreq_init() after commit d15ce412737a ("ACPI:
> cpufreq: Switch to QoS requests instead of cpufreq notifier")
> which didn't add the requisite NULL pointer checks in there.
>
> Add the NULL pointer checks to acpi_processor_ppc_init() and
> acpi_thermal_cpufreq_init(), and to the corresponding "exit"
> routines.
>
> While at it, drop redundant return instructions from
> acpi_processor_ppc_init() and acpi_thermal_cpufreq_init().
>
> Fixes: d15ce412737a ("ACPI: cpufreq: Switch to QoS requests instead of cpufreq notifier")
> Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/acpi/processor_perflib.c | 10 ++++++----
> drivers/acpi/processor_thermal.c | 10 ++++++----
> 2 files changed, 12 insertions(+), 8 deletions(-)

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

--
viresh