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ACPI: scan: Fix race related to dropping dependencies

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If acpi_add_single_object() runs concurrently with respect to
acpi_scan_clear_dep() which deletes a dependencies list entry where
the device being added is the consumer, the device's dep_unmet
counter may not be updated to reflect that change.

Namely, if the dependencies list entry is deleted right after
calling acpi_scan_dep_init() and before calling acpi_device_add(),
acpi_scan_clear_dep() will not find the device object corresponding
to the consumer device ACPI handle and it will not update its
dep_unmet counter to reflect the deletion of the list entry.
Consequently, the dep_unmet counter of the device will never
become zero going forward which may prevent it from being
completely enumerated.

To address this problem, modify acpi_add_single_object() to run
acpi_tie_acpi_dev(), to attach the ACPI device object created by it
to the corresponding ACPI namespace node, under acpi_dep_list_lock
along with acpi_scan_dep_init() whenever the latter is called.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Rafael J. Wysocki 2021-06-17 15:57:07 +02:00
parent c6a493a1b6
commit 5f4ce26078
1 changed files with 32 additions and 13 deletions
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45
drivers/acpi/scan.c
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@ -650,16 +650,12 @@ static int acpi_tie_acpi_dev(struct acpi_device *adev)
return 0;
}
int acpi_device_add(struct acpi_device *device,
void (*release)(struct device *))
static int __acpi_device_add(struct acpi_device *device,
void (*release)(struct device *))
{
struct acpi_device_bus_id *acpi_device_bus_id;
int result;
result = acpi_tie_acpi_dev(device);
if (result)
return result;
/*
* Linkage
* -------
@ -748,6 +744,17 @@ int acpi_device_add(struct acpi_device *device,
return result;
}
int acpi_device_add(struct acpi_device *adev, void (*release)(struct device *))
{
int ret;
ret = acpi_tie_acpi_dev(adev);
if (ret)
return ret;
return __acpi_device_add(adev, release);
}
/* --------------------------------------------------------------------------
Device Enumeration
-------------------------------------------------------------------------- */
@ -1675,14 +1682,10 @@ static void acpi_scan_dep_init(struct acpi_device *adev)
{
struct acpi_dep_data *dep;
mutex_lock(&acpi_dep_list_lock);
list_for_each_entry(dep, &acpi_dep_list, node) {
if (dep->consumer == adev->handle)
adev->dep_unmet++;
}
mutex_unlock(&acpi_dep_list_lock);
}
void acpi_device_add_finalize(struct acpi_device *device)
@ -1701,6 +1704,7 @@ static int acpi_add_single_object(struct acpi_device **child,
acpi_handle handle, int type, bool dep_init)
{
struct acpi_device *device;
bool release_dep_lock = false;
int result;
device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL);
@ -1714,16 +1718,31 @@ static int acpi_add_single_object(struct acpi_device **child,
* this must be done before the get power-/wakeup_dev-flags calls.
*/
if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR) {
if (dep_init)
if (dep_init) {
mutex_lock(&acpi_dep_list_lock);
/*
* Hold the lock until the acpi_tie_acpi_dev() call
* below to prevent concurrent acpi_scan_clear_dep()
* from deleting a dependency list entry without
* updating dep_unmet for the device.
*/
release_dep_lock = true;
acpi_scan_dep_init(device);
}
acpi_scan_init_status(device);
}
acpi_bus_get_power_flags(device);
acpi_bus_get_wakeup_device_flags(device);
result = acpi_device_add(device, acpi_device_release);
result = acpi_tie_acpi_dev(device);
if (release_dep_lock)
mutex_unlock(&acpi_dep_list_lock);
if (!result)
result = __acpi_device_add(device, acpi_device_release);
if (result) {
acpi_device_release(&device->dev);
return result;