From 21eb93f432b1a785df193df1a56a59e9eb3a985f Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Fri, 21 Feb 2020 00:05:08 -0800 Subject: driver core: Call sync_state() even if supplier has no consumers The initial patch that added sync_state() support didn't handle the case where a supplier has no consumers. This was because when a device is successfully bound with a driver, only its suppliers were checked to see if they are eligible to get a sync_state(). This is not sufficient for devices that have no consumers but still need to do device state clean up. So fix this. Fixes: fc5a251d0fd7ca90 (driver core: Add sync_state driver/bus callback) Signed-off-by: Saravana Kannan Cc: stable Link: https://lore.kernel.org/r/20200221080510.197337-2-saravanak@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/core.c b/drivers/base/core.c index 42a672456432..3306d5ae92a6 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -745,25 +745,31 @@ static void __device_links_queue_sync_state(struct device *dev, /** * device_links_flush_sync_list - Call sync_state() on a list of devices * @list: List of devices to call sync_state() on + * @dont_lock_dev: Device for which lock is already held by the caller * * Calls sync_state() on all the devices that have been queued for it. This - * function is used in conjunction with __device_links_queue_sync_state(). + * function is used in conjunction with __device_links_queue_sync_state(). The + * @dont_lock_dev parameter is useful when this function is called from a + * context where a device lock is already held. */ -static void device_links_flush_sync_list(struct list_head *list) +static void device_links_flush_sync_list(struct list_head *list, + struct device *dont_lock_dev) { struct device *dev, *tmp; list_for_each_entry_safe(dev, tmp, list, links.defer_sync) { list_del_init(&dev->links.defer_sync); - device_lock(dev); + if (dev != dont_lock_dev) + device_lock(dev); if (dev->bus->sync_state) dev->bus->sync_state(dev); else if (dev->driver && dev->driver->sync_state) dev->driver->sync_state(dev); - device_unlock(dev); + if (dev != dont_lock_dev) + device_unlock(dev); put_device(dev); } @@ -801,7 +807,7 @@ void device_links_supplier_sync_state_resume(void) out: device_links_write_unlock(); - device_links_flush_sync_list(&sync_list); + device_links_flush_sync_list(&sync_list, NULL); } static int sync_state_resume_initcall(void) @@ -865,6 +871,11 @@ void device_links_driver_bound(struct device *dev) driver_deferred_probe_add(link->consumer); } + if (defer_sync_state_count) + __device_links_supplier_defer_sync(dev); + else + __device_links_queue_sync_state(dev, &sync_list); + list_for_each_entry(link, &dev->links.suppliers, c_node) { if (!(link->flags & DL_FLAG_MANAGED)) continue; @@ -883,7 +894,7 @@ void device_links_driver_bound(struct device *dev) device_links_write_unlock(); - device_links_flush_sync_list(&sync_list); + device_links_flush_sync_list(&sync_list, dev); } static void device_link_drop_managed(struct device_link *link) -- cgit v1.2.3 From 77036165d8bcf7c7b2a2df28a601ec2c52bb172d Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Fri, 21 Feb 2020 00:05:10 -0800 Subject: driver core: Skip unnecessary work when device doesn't have sync_state() A bunch of busy work is done for devices that don't have sync_state() support. Stop doing the busy work. Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20200221080510.197337-4-saravanak@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/base') diff --git a/drivers/base/core.c b/drivers/base/core.c index 3306d5ae92a6..dbb0f9130f42 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -718,6 +718,8 @@ static void __device_links_queue_sync_state(struct device *dev, { struct device_link *link; + if (!dev_has_sync_state(dev)) + return; if (dev->state_synced) return; @@ -819,7 +821,7 @@ late_initcall(sync_state_resume_initcall); static void __device_links_supplier_defer_sync(struct device *sup) { - if (list_empty(&sup->links.defer_sync)) + if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup)) list_add_tail(&sup->links.defer_sync, &deferred_sync); } -- cgit v1.2.3 From 7589238a8cf37331607c3222a64ac3140b29532d Mon Sep 17 00:00:00 2001 From: Brendan Higgins Date: Thu, 27 Feb 2020 16:00:01 -0800 Subject: Revert "software node: Simplify software_node_release() function" This reverts commit 3df85a1ae51f6b256982fe9d17c2dc5bfb4cc402. The reverted commit says "It's possible to release the node ID immediately when fwnode_remove_software_node() is called, no need to wait for software_node_release() with that." However, releasing the node ID before waiting for software_node_release() to be called causes the node ID to be released before the kobject and the underlying sysfs entry; this means there is a period of time where a sysfs entry exists that is associated with an unallocated node ID. Once consequence of this is that there is a race condition where it is possible to call fwnode_create_software_node() with no parent node specified (NULL) and have it fail with -EEXIST because the node ID that was assigned is still associated with a stale sysfs entry that hasn't been cleaned up yet. Although it is difficult to reproduce this race condition under normal conditions, it can be deterministically reproduced with the following minconfig on UML: CONFIG_KUNIT_DRIVER_PE_TEST=y CONFIG_DEBUG_KERNEL=y CONFIG_DEBUG_OBJECTS=y CONFIG_DEBUG_OBJECTS_TIMERS=y CONFIG_DEBUG_KOBJECT_RELEASE=y CONFIG_KUNIT=y Running the tests with this configuration causes the following failure: kobject: 'node0' ((____ptrval____)): kobject_release, parent (____ptrval____) (delayed 400) ok 1 - pe_test_uints sysfs: cannot create duplicate filename '/kernel/software_nodes/node0' CPU: 0 PID: 28 Comm: kunit_try_catch Not tainted 5.6.0-rc3-next-20200227 #14 kobject_add_internal failed for node0 with -EEXIST, don't try to register things with the same name in the same directory. kobject: 'node0' ((____ptrval____)): kobject_release, parent (____ptrval____) (delayed 100) # pe_test_uint_arrays: ASSERTION FAILED at drivers/base/test/property-entry-test.c:123 Expected node is not error, but is: -17 not ok 2 - pe_test_uint_arrays Reported-by: Heidi Fahim Signed-off-by: Brendan Higgins Reviewed-by: Heikki Krogerus Cc: 5.3+ # 5.3+ Signed-off-by: Rafael J. Wysocki --- drivers/base/swnode.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c index 0b081dee1e95..de8d3543e8fe 100644 --- a/drivers/base/swnode.c +++ b/drivers/base/swnode.c @@ -608,6 +608,13 @@ static void software_node_release(struct kobject *kobj) { struct swnode *swnode = kobj_to_swnode(kobj); + if (swnode->parent) { + ida_simple_remove(&swnode->parent->child_ids, swnode->id); + list_del(&swnode->entry); + } else { + ida_simple_remove(&swnode_root_ids, swnode->id); + } + if (swnode->allocated) { property_entries_free(swnode->node->properties); kfree(swnode->node); @@ -773,13 +780,6 @@ void fwnode_remove_software_node(struct fwnode_handle *fwnode) if (!swnode) return; - if (swnode->parent) { - ida_simple_remove(&swnode->parent->child_ids, swnode->id); - list_del(&swnode->entry); - } else { - ida_simple_remove(&swnode_root_ids, swnode->id); - } - kobject_put(&swnode->kobj); } EXPORT_SYMBOL_GPL(fwnode_remove_software_node); -- cgit v1.2.3