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ACPI: scan: Fix device object rescan in acpi_scan_clear_dep()

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In general, acpi_bus_attach() can only be run safely under
acpi_scan_lock, but that lock cannot be acquired under
acpi_dep_list_lock, so make acpi_scan_clear_dep() schedule deferred
execution of acpi_bus_attach() under acpi_scan_lock instead of
calling it directly.

This also fixes a possible race between acpi_scan_clear_dep() and
device removal that might cause a device object that went away to
be accessed, because acpi_scan_clear_dep() is changed to acquire
a reference on the consumer device object.

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 2021-06-16 16:23:44 +02:00
parent aff0dbd03d
commit dc612486c9
1 changed files with 45 additions and 5 deletions
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50
drivers/acpi/scan.c
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@ -2109,16 +2109,56 @@ static int acpi_dev_get_first_consumer_dev_cb(struct acpi_dep_data *dep, void *d
return 0;
}
struct acpi_scan_clear_dep_work {
struct work_struct work;
struct acpi_device *adev;
};
static void acpi_scan_clear_dep_fn(struct work_struct *work)
{
struct acpi_scan_clear_dep_work *cdw;
cdw = container_of(work, struct acpi_scan_clear_dep_work, work);
acpi_scan_lock_acquire();
acpi_bus_attach(cdw->adev, true);
acpi_scan_lock_release();
acpi_dev_put(cdw->adev);
kfree(cdw);
}
static bool acpi_scan_clear_dep_queue(struct acpi_device *adev)
{
struct acpi_scan_clear_dep_work *cdw;
if (adev->dep_unmet)
return false;
cdw = kmalloc(sizeof(*cdw), GFP_KERNEL);
if (!cdw)
return false;
cdw->adev = adev;
INIT_WORK(&cdw->work, acpi_scan_clear_dep_fn);
/*
* Since the work function may block on the lock until the entire
* initial enumeration of devices is complete, put it into the unbound
* workqueue.
*/
queue_work(system_unbound_wq, &cdw->work);
return true;
}
static int acpi_scan_clear_dep(struct acpi_dep_data *dep, void *data)
{
struct acpi_device *adev;
acpi_bus_get_device(dep->consumer, &adev);
struct acpi_device *adev = acpi_bus_get_acpi_device(dep->consumer);
if (adev) {
adev->dep_unmet--;
if (!adev->dep_unmet)
acpi_bus_attach(adev, true);
if (!acpi_scan_clear_dep_queue(adev))
acpi_dev_put(adev);
}
list_del(&dep->node);