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Power management fixes for 5.19-rc6

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- Fix NULL pointer dereference related to printing a diagnostic
    message in the exynos-bus devfreq driver (Christian Marangi).
 
  - Fix race condition in the runtime PM framework which in some
    cases may cause a supplier device to be suspended when its
    consumer is still active (Rafael Wysocki).
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Merge tag 'pm-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "These fix a NULL pointer dereference in a devfreq driver and a runtime
  PM framework issue that may cause a supplier device to be suspended
  before its consumer.

  Specifics:

   - Fix NULL pointer dereference related to printing a diagnostic
     message in the exynos-bus devfreq driver (Christian Marangi)

   - Fix race condition in the runtime PM framework which in some cases
     may cause a supplier device to be suspended when its consumer is
     still active (Rafael Wysocki)"

* tag 'pm-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / devfreq: exynos-bus: Fix NULL pointer dereference
  PM: runtime: Fix supplier device management during consumer probe
  PM: runtime: Redefine pm_runtime_release_supplier()
This commit is contained in:
Linus Torvalds 2022-07-08 13:01:04 -07:00
commit 3784fad934
4 changed files with 27 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/base/core.c
View File

@ -486,7 +486,18 @@ static void device_link_release_fn(struct work_struct *work)
/* Ensure that all references to the link object have been dropped. */
device_link_synchronize_removal();
pm_runtime_release_supplier(link, true);
pm_runtime_release_supplier(link);
/*
* If supplier_preactivated is set, the link has been dropped between
* the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
* in __driver_probe_device(). In that case, drop the supplier's
* PM-runtime usage counter to remove the reference taken by
* pm_runtime_get_suppliers().
*/
if (link->supplier_preactivated)
pm_runtime_put_noidle(link->supplier);
pm_request_idle(link->supplier);
put_device(link->consumer);
put_device(link->supplier);

34
drivers/base/power/runtime.c
View File

@ -308,13 +308,10 @@ static int rpm_get_suppliers(struct device *dev)
/**
* pm_runtime_release_supplier - Drop references to device link's supplier.
* @link: Target device link.
* @check_idle: Whether or not to check if the supplier device is idle.
*
* Drop all runtime PM references associated with @link to its supplier device
* and if @check_idle is set, check if that device is idle (and so it can be
* suspended).
* Drop all runtime PM references associated with @link to its supplier device.
*/
void pm_runtime_release_supplier(struct device_link *link, bool check_idle)
void pm_runtime_release_supplier(struct device_link *link)
{
struct device *supplier = link->supplier;
@ -327,9 +324,6 @@ void pm_runtime_release_supplier(struct device_link *link, bool check_idle)
while (refcount_dec_not_one(&link->rpm_active) &&
atomic_read(&supplier->power.usage_count) > 0)
pm_runtime_put_noidle(supplier);
if (check_idle)
pm_request_idle(supplier);
}
static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
@ -337,8 +331,11 @@ static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
struct device_link *link;
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
device_links_read_lock_held())
pm_runtime_release_supplier(link, try_to_suspend);
device_links_read_lock_held()) {
pm_runtime_release_supplier(link);
if (try_to_suspend)
pm_request_idle(link->supplier);
}
}
static void rpm_put_suppliers(struct device *dev)
@ -1771,7 +1768,6 @@ void pm_runtime_get_suppliers(struct device *dev)
if (link->flags & DL_FLAG_PM_RUNTIME) {
link->supplier_preactivated = true;
pm_runtime_get_sync(link->supplier);
refcount_inc(&link->rpm_active);
}
device_links_read_unlock(idx);
@ -1791,19 +1787,8 @@ void pm_runtime_put_suppliers(struct device *dev)
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
device_links_read_lock_held())
if (link->supplier_preactivated) {
bool put;
link->supplier_preactivated = false;
spin_lock_irq(&dev->power.lock);
put = pm_runtime_status_suspended(dev) &&
refcount_dec_not_one(&link->rpm_active);
spin_unlock_irq(&dev->power.lock);
if (put)
pm_runtime_put(link->supplier);
pm_runtime_put(link->supplier);
}
device_links_read_unlock(idx);
@ -1838,7 +1823,8 @@ void pm_runtime_drop_link(struct device_link *link)
return;
pm_runtime_drop_link_count(link->consumer);
pm_runtime_release_supplier(link, true);
pm_runtime_release_supplier(link);
pm_request_idle(link->supplier);
}
static bool pm_runtime_need_not_resume(struct device *dev)

6
drivers/devfreq/exynos-bus.c
View File

@ -447,9 +447,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
}
}
max_state = bus->devfreq->profile->max_state;
min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
max_state = bus->devfreq->max_state;
min_freq = (bus->devfreq->freq_table[0] / 1000);
max_freq = (bus->devfreq->freq_table[max_state - 1] / 1000);
pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
dev_name(dev), min_freq, max_freq);

5
include/linux/pm_runtime.h
View File

@ -88,7 +88,7 @@ extern void pm_runtime_get_suppliers(struct device *dev);
extern void pm_runtime_put_suppliers(struct device *dev);
extern void pm_runtime_new_link(struct device *dev);
extern void pm_runtime_drop_link(struct device_link *link);
extern void pm_runtime_release_supplier(struct device_link *link, bool check_idle);
extern void pm_runtime_release_supplier(struct device_link *link);
extern int devm_pm_runtime_enable(struct device *dev);
@ -314,8 +314,7 @@ static inline void pm_runtime_get_suppliers(struct device *dev) {}
static inline void pm_runtime_put_suppliers(struct device *dev) {}
static inline void pm_runtime_new_link(struct device *dev) {}
static inline void pm_runtime_drop_link(struct device_link *link) {}
static inline void pm_runtime_release_supplier(struct device_link *link,
bool check_idle) {}
static inline void pm_runtime_release_supplier(struct device_link *link) {}
#endif /* !CONFIG_PM */