From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
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@xxxxxxxxx>
Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
-> v2:
* Fix memory leak spotted by Hans.
* Add the R-by tag from Hans.
---
drivers/acpi/scan.c | 50 ++++++++++++++++++++++++++++++++------------------
1 file changed, 32 insertions(+), 18 deletions(-)
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -657,16 +652,12 @@ static int acpi_tie_acpi_dev(struct acpi
return 0;
}
-int acpi_device_add(struct acpi_device *device,
- void (*release)(struct device *))
+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
* -------
@@ -755,6 +746,17 @@ err_unlock:
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
-------------------------------------------------------------------------- */
@@ -1681,14 +1683,10 @@ static void acpi_scan_dep_init(struct ac
{
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)
@@ -1707,6 +1705,7 @@ static int acpi_add_single_object(struct
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);
@@ -1720,16 +1719,31 @@ static int acpi_add_single_object(struct
* 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;
