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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-06-17 15:57:07 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-06-17 15:57:07 +0200
commit5f4ce26078fde9cd406c008ba35e31bbb26a23a1 (patch)
tree02b429ff48fc0b3518058f8d011239f2ac3c4e0b /drivers/acpi
parentc6a493a1b603ed216ce69d1faac3f0ddc6a2f8eb (diff)
downloadlinux-5f4ce26078fde9cd406c008ba35e31bbb26a23a1.tar.bz2
ACPI: scan: Fix race related to dropping dependencies
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>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/scan.c45
1 files changed, 32 insertions, 13 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index c62ce287fdb9..1c6205661000 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -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 @@ 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
-------------------------------------------------------------------------- */
@@ -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;