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Subject[149/272] cpuidle: Make cpuidle_enable_device() call poll_idle_init()
2.6.37-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Rafael J. Wysocki <rjw@sisk.pl>

commit d8c216cfa57e8a579f41729cbb88c97835d9ac8d upstream.

The following scenario is possible with the current cpuidle code and
the ACPI cpuidle driver:
(1) acpi_processor_cst_has_changed() is called,
(2) cpuidle_disable_device() is called,
(3) cpuidle_remove_state_sysfs() is called to remove the (presumably
outdated) states info from sysfs,
(3) acpi_processor_get_power_info() is called, the first entry in the
pr->power.states[] table is filled with zeros,
(4) acpi_processor_setup_cpuidle() is called and it doesn't fill the
first entry in pr->power.states[],
(5) cpuidle_enable_device() is called,
(6) __cpuidle_register_device() is _not_ called, since the device has
already been registered,
(7) Consequently, poll_idle_init() is _not_ called either,
(8) cpuidle_add_state_sysfs() is called to create the sysfs attributes
for the new states and it uses the bogus first table entry from
acpi_processor_get_power_info() for creating state0.

This problem is avoided if cpuidle_enable_device()
unconditionally calls poll_idle_init().

Reported-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/cpuidle/cpuidle.c | 82 +++++++++++++++++++++++-----------------------
1 file changed, 41 insertions(+), 41 deletions(-)

--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -154,6 +154,45 @@ void cpuidle_resume_and_unlock(void)

EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);

+#ifdef CONFIG_ARCH_HAS_CPU_RELAX
+static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st)
+{
+ ktime_t t1, t2;
+ s64 diff;
+ int ret;
+
+ t1 = ktime_get();
+ local_irq_enable();
+ while (!need_resched())
+ cpu_relax();
+
+ t2 = ktime_get();
+ diff = ktime_to_us(ktime_sub(t2, t1));
+ if (diff > INT_MAX)
+ diff = INT_MAX;
+
+ ret = (int) diff;
+ return ret;
+}
+
+static void poll_idle_init(struct cpuidle_device *dev)
+{
+ struct cpuidle_state *state = &dev->states[0];
+
+ cpuidle_set_statedata(state, NULL);
+
+ snprintf(state->name, CPUIDLE_NAME_LEN, "C0");
+ snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
+ state->exit_latency = 0;
+ state->target_residency = 0;
+ state->power_usage = -1;
+ state->flags = CPUIDLE_FLAG_POLL;
+ state->enter = poll_idle;
+}
+#else
+static void poll_idle_init(struct cpuidle_device *dev) {}
+#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
+
/**
* cpuidle_enable_device - enables idle PM for a CPU
* @dev: the CPU
@@ -178,6 +217,8 @@ int cpuidle_enable_device(struct cpuidle
return ret;
}

+ poll_idle_init(dev);
+
if ((ret = cpuidle_add_state_sysfs(dev)))
return ret;

@@ -232,45 +273,6 @@ void cpuidle_disable_device(struct cpuid

EXPORT_SYMBOL_GPL(cpuidle_disable_device);

-#ifdef CONFIG_ARCH_HAS_CPU_RELAX
-static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st)
-{
- ktime_t t1, t2;
- s64 diff;
- int ret;
-
- t1 = ktime_get();
- local_irq_enable();
- while (!need_resched())
- cpu_relax();
-
- t2 = ktime_get();
- diff = ktime_to_us(ktime_sub(t2, t1));
- if (diff > INT_MAX)
- diff = INT_MAX;
-
- ret = (int) diff;
- return ret;
-}
-
-static void poll_idle_init(struct cpuidle_device *dev)
-{
- struct cpuidle_state *state = &dev->states[0];
-
- cpuidle_set_statedata(state, NULL);
-
- snprintf(state->name, CPUIDLE_NAME_LEN, "C0");
- snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
- state->exit_latency = 0;
- state->target_residency = 0;
- state->power_usage = -1;
- state->flags = CPUIDLE_FLAG_POLL;
- state->enter = poll_idle;
-}
-#else
-static void poll_idle_init(struct cpuidle_device *dev) {}
-#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
-
/**
* __cpuidle_register_device - internal register function called before register
* and enable routines
@@ -291,8 +293,6 @@ static int __cpuidle_register_device(str

init_completion(&dev->kobj_unregister);

- poll_idle_init(dev);
-
/*
* cpuidle driver should set the dev->power_specified bit
* before registering the device if the driver provides



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