From 2d8b39a62a5d386a73f339e46fe05354a3a4895b Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 15 Oct 2019 19:35:20 +0200 Subject: [PATCH] ACPI: processor: Avoid NULL pointer dereferences at init time 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 Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar --- drivers/acpi/processor_perflib.c | 10 ++++++---- drivers/acpi/processor_thermal.c | 10 ++++++---- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c index 2261713d1aec..930a49fa4dfc 100644 --- a/drivers/acpi/processor_perflib.c +++ b/drivers/acpi/processor_perflib.c @@ -162,21 +162,23 @@ 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); - dev_pm_qos_remove_request(&pr->perflib_req); + if (pr) + dev_pm_qos_remove_request(&pr->perflib_req); } static int acpi_processor_get_performance_control(struct acpi_processor *pr) diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c index ec2638f1df4f..8227c7dd75b1 100644 --- a/drivers/acpi/processor_thermal.c +++ b/drivers/acpi/processor_thermal.c @@ -130,21 +130,23 @@ 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); - dev_pm_qos_remove_request(&pr->thermal_req); + if (pr) + dev_pm_qos_remove_request(&pr->thermal_req); } #else /* ! CONFIG_CPU_FREQ */ static int cpufreq_get_max_state(unsigned int cpu) -- 2.39.5