acpi, nfit: fix module unload vs workqueue shutdown race
The workqueue may still be running when the devres callbacks start
firing to deallocate an acpi_nfit_desc instance. Stop and flush the
workqueue before letting any other devres de-allocations proceed.
Reported-by: Linda Knippers <linda.knippers@hpe.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 69c6cc7..261eea1 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2604,7 +2604,8 @@ static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
return rc;
}
- queue_work(nfit_wq, &acpi_desc->work);
+ if (!acpi_desc->cancel)
+ queue_work(nfit_wq, &acpi_desc->work);
return 0;
}
@@ -2650,32 +2651,11 @@ static int acpi_nfit_desc_init_scrub_attr(struct acpi_nfit_desc *acpi_desc)
return 0;
}
-static void acpi_nfit_destruct(void *data)
+static void acpi_nfit_unregister(void *data)
{
struct acpi_nfit_desc *acpi_desc = data;
- struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
- /*
- * Destruct under acpi_desc_lock so that nfit_handle_mce does not
- * race teardown
- */
- mutex_lock(&acpi_desc_lock);
- acpi_desc->cancel = 1;
- /*
- * Bounce the nvdimm bus lock to make sure any in-flight
- * acpi_nfit_ars_rescan() submissions have had a chance to
- * either submit or see ->cancel set.
- */
- device_lock(bus_dev);
- device_unlock(bus_dev);
-
- flush_workqueue(nfit_wq);
- if (acpi_desc->scrub_count_state)
- sysfs_put(acpi_desc->scrub_count_state);
nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
- acpi_desc->nvdimm_bus = NULL;
- list_del(&acpi_desc->list);
- mutex_unlock(&acpi_desc_lock);
}
int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
@@ -2693,7 +2673,7 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
if (!acpi_desc->nvdimm_bus)
return -ENOMEM;
- rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
+ rc = devm_add_action_or_reset(dev, acpi_nfit_unregister,
acpi_desc);
if (rc)
return rc;
@@ -2787,9 +2767,10 @@ static int acpi_nfit_flush_probe(struct nvdimm_bus_descriptor *nd_desc)
/* bounce the init_mutex to make init_complete valid */
mutex_lock(&acpi_desc->init_mutex);
- mutex_unlock(&acpi_desc->init_mutex);
- if (acpi_desc->init_complete)
+ if (acpi_desc->cancel || acpi_desc->init_complete) {
+ mutex_unlock(&acpi_desc->init_mutex);
return 0;
+ }
/*
* Scrub work could take 10s of seconds, userspace may give up so we
@@ -2798,6 +2779,7 @@ static int acpi_nfit_flush_probe(struct nvdimm_bus_descriptor *nd_desc)
INIT_WORK_ONSTACK(&flush.work, flush_probe);
COMPLETION_INITIALIZER_ONSTACK(flush.cmp);
queue_work(nfit_wq, &flush.work);
+ mutex_unlock(&acpi_desc->init_mutex);
rc = wait_for_completion_interruptible(&flush.cmp);
cancel_work_sync(&flush.work);
@@ -2834,10 +2816,12 @@ int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
if (work_busy(&acpi_desc->work))
return -EBUSY;
- if (acpi_desc->cancel)
- return 0;
-
mutex_lock(&acpi_desc->init_mutex);
+ if (acpi_desc->cancel) {
+ mutex_unlock(&acpi_desc->init_mutex);
+ return 0;
+ }
+
list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
struct acpi_nfit_system_address *spa = nfit_spa->spa;
@@ -2886,6 +2870,35 @@ static void acpi_nfit_put_table(void *table)
acpi_put_table(table);
}
+void acpi_nfit_shutdown(void *data)
+{
+ struct acpi_nfit_desc *acpi_desc = data;
+ struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+
+ /*
+ * Destruct under acpi_desc_lock so that nfit_handle_mce does not
+ * race teardown
+ */
+ mutex_lock(&acpi_desc_lock);
+ list_del(&acpi_desc->list);
+ mutex_unlock(&acpi_desc_lock);
+
+ mutex_lock(&acpi_desc->init_mutex);
+ acpi_desc->cancel = 1;
+ mutex_unlock(&acpi_desc->init_mutex);
+
+ /*
+ * Bounce the nvdimm bus lock to make sure any in-flight
+ * acpi_nfit_ars_rescan() submissions have had a chance to
+ * either submit or see ->cancel set.
+ */
+ device_lock(bus_dev);
+ device_unlock(bus_dev);
+
+ flush_workqueue(nfit_wq);
+}
+EXPORT_SYMBOL_GPL(acpi_nfit_shutdown);
+
static int acpi_nfit_add(struct acpi_device *adev)
{
struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
@@ -2933,12 +2946,15 @@ static int acpi_nfit_add(struct acpi_device *adev)
rc = acpi_nfit_init(acpi_desc, (void *) tbl
+ sizeof(struct acpi_table_nfit),
sz - sizeof(struct acpi_table_nfit));
- return rc;
+
+ if (rc)
+ return rc;
+ return devm_add_action_or_reset(dev, acpi_nfit_shutdown, acpi_desc);
}
static int acpi_nfit_remove(struct acpi_device *adev)
{
- /* see acpi_nfit_destruct */
+ /* see acpi_nfit_unregister */
return 0;
}