ACPI: processor: Avoid NULL pointer dereferences at init time (2d8b39a6) · Commits · 戴 / test

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 ("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: ("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> Acked-by:

Viresh Kumar <viresh.kumar@linaro.org>

drivers/acpi/processor_perflib.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -162,20 +162,22 @@ void acpi_processor_ppc_init(int cpu)
		struct acpi_processor *pr = per_cpu(processors, cpu);
		int ret;

		if (!pr)
		return;

		ret = dev_pm_qos_add_request(get_cpu_device(cpu),
		&pr->perflib_req, DEV_PM_QOS_MAX_FREQUENCY,
		INT_MAX);
		if (ret < 0) {
		if (ret < 0)
		pr_err("Failed to add freq constraint for CPU%d (%d)\n", cpu,
		ret);
		return;
		}
		}

		void acpi_processor_ppc_exit(int cpu)
		{
		struct acpi_processor *pr = per_cpu(processors, cpu);

		if (pr)
		dev_pm_qos_remove_request(&pr->perflib_req);
		}

drivers/acpi/processor_thermal.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -130,20 +130,22 @@ void acpi_thermal_cpufreq_init(int cpu)
		struct acpi_processor *pr = per_cpu(processors, cpu);
		int ret;

		if (!pr)
		return;

		ret = dev_pm_qos_add_request(get_cpu_device(cpu),
		&pr->thermal_req, DEV_PM_QOS_MAX_FREQUENCY,
		INT_MAX);
		if (ret < 0) {
		if (ret < 0)
		pr_err("Failed to add freq constraint for CPU%d (%d)\n", cpu,
		ret);
		return;
		}
		}

		void acpi_thermal_cpufreq_exit(int cpu)
		{
		struct acpi_processor *pr = per_cpu(processors, cpu);

		if (pr)
		dev_pm_qos_remove_request(&pr->thermal_req);
		}
		#else /* ! CONFIG_CPU_FREQ */

Admin message