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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-10-15 20:35:20 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-10-16 14:02:45 +0300
commit2d8b39a62a5d386a73f339e46fe05354a3a4895b (patch)
tree278bb10df8488575ff7e8fb9d52cd09ebeda2180 /drivers/acpi/processor_perflib.c
parent65650b35133ff20f0c9ef0abd5c3c66dbce3ae57 (diff)
downloadlinux-2d8b39a62a5d386a73f339e46fe05354a3a4895b.tar.xz
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 <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'drivers/acpi/processor_perflib.c')
-rw-r--r--drivers/acpi/processor_perflib.c10
1 files changed, 6 insertions, 4 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)