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cpuidle: Make cpuidle_enable_device() call poll_idle_init() 

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    outdated) states info from sysfs,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>
cc: stable@kernel.org
This commit is contained in:
Rafael J. Wysocki 2011-01-08 00:29:20 +01:00 committed by Len Brown
parent ddbd550d50
commit d8c216cfa5
1 changed files with 41 additions and 41 deletions
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82
drivers/cpuidle/cpuidle.c
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@ -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_device *dev)
return ret;
}
poll_idle_init(dev);
if ((ret = cpuidle_add_state_sysfs(dev)))
return ret;
@ -232,45 +273,6 @@ void cpuidle_disable_device(struct cpuidle_device *dev)
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(struct cpuidle_device *dev)
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