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author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2021-06-16 16:23:44 +0200 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2021-06-17 15:56:03 +0200 |
commit | dc612486c91983a113adefedac030575ea7a4c4a (patch) | |
tree | 18f9e63707075079aa0ff9b2ec6a95e91ee2c4d9 /drivers/acpi/scan.c | |
parent | aff0dbd03d3b750e2331f7cb93e01fe25ed27086 (diff) | |
download | linux-stable-dc612486c91983a113adefedac030575ea7a4c4a.tar.gz linux-stable-dc612486c91983a113adefedac030575ea7a4c4a.tar.bz2 linux-stable-dc612486c91983a113adefedac030575ea7a4c4a.zip |
ACPI: scan: Fix device object rescan in acpi_scan_clear_dep()
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>
Diffstat (limited to 'drivers/acpi/scan.c')
-rw-r--r-- | drivers/acpi/scan.c | 50 |
1 files changed, 45 insertions, 5 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index b7f9b7ac0d04..b0bdd9b90e44 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -2109,16 +2109,56 @@ static int acpi_dev_get_first_consumer_dev_cb(struct acpi_dep_data *dep, void *d return 0; } -static int acpi_scan_clear_dep(struct acpi_dep_data *dep, void *data) -{ +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; - acpi_bus_get_device(dep->consumer, &adev); + 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_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); |