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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 d15ce41273 ("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: d15ce41273 ("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>
alistair/sunxi64-5.4-dsi
Rafael J. Wysocki 2019-10-15 19:35:20 +02:00
parent 65650b3513
commit 2d8b39a62a
2 changed files with 12 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/acpi/processor_perflib.c
View File

@ -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)

10
drivers/acpi/processor_thermal.c
View File

@ -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)