From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux ACPI <linux-acpi@vger.kernel.org>
Cc: Linux PM <linux-pm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Viresh Kumar <viresh.kumar@linaro.org>
Subject: [PATCH] ACPI: processor: Avoid NULL pointer dereferences at init time
Date: Tue, 15 Oct 2019 19:35:20 +0200 [thread overview]
Message-ID: <9765491.cFa8AugBjT@kreacher> (raw)
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(-)
Index: linux-pm/drivers/acpi/processor_perflib.c
===================================================================
--- linux-pm.orig/drivers/acpi/processor_perflib.c
+++ linux-pm/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)
Index: linux-pm/drivers/acpi/processor_thermal.c
===================================================================
--- linux-pm.orig/drivers/acpi/processor_thermal.c
+++ linux-pm/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)
next reply other threads:[~2019-10-15 17:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-15 17:35 Rafael J. Wysocki [this message]
2019-10-16 3:38 ` [PATCH] ACPI: processor: Avoid NULL pointer dereferences at init time Viresh Kumar
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