Merge tag 'driver-core-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core patches from Greg KH:
 "Here's the big driver core pull request for 3.12-rc1.

  Lots of tiny changes here fixing up the way sysfs attributes are
  created, to try to make drivers simpler, and fix a whole class race
  conditions with creations of device attributes after the device was
  announced to userspace.

  All the various pieces are acked by the different subsystem
  maintainers"

* tag 'driver-core-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (119 commits)
  firmware loader: fix pending_fw_head list corruption
  drivers/base/memory.c: introduce help macro to_memory_block
  dynamic debug: line queries failing due to uninitialized local variable
  sysfs: sysfs_create_groups returns a value.
  debugfs: provide debugfs_create_x64() when disabled
  rbd: convert bus code to use bus_groups
  firmware: dcdbas: use binary attribute groups
  sysfs: add sysfs_create/remove_groups for when SYSFS is not enabled
  driver core: add #include <linux/sysfs.h> to core files.
  HID: convert bus code to use dev_groups
  Input: serio: convert bus code to use drv_groups
  Input: gameport: convert bus code to use drv_groups
  driver core: firmware: use __ATTR_RW()
  driver core: core: use DEVICE_ATTR_RO
  driver core: bus: use DRIVER_ATTR_WO()
  driver core: create write-only attribute macros for devices and drivers
  sysfs: create __ATTR_WO()
  driver-core: platform: convert bus code to use dev_groups
  workqueue: convert bus code to use dev_groups
  MEI: convert bus code to use dev_groups
  ...

3 files changed, 39 insertions, 4 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1501aa5..444e1c1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -981,6 +981,25 @@ config DEBUG_KOBJECT
 	  If you say Y here, some extra kobject debugging messages will be sent
 	  to the syslog. 
 
+config DEBUG_KOBJECT_RELEASE
+	bool "kobject release debugging"
+	depends on DEBUG_KERNEL
+	help
+	  kobjects are reference counted objects.  This means that their
+	  last reference count put is not predictable, and the kobject can
+	  live on past the point at which a driver decides to drop it's
+	  initial reference to the kobject gained on allocation.  An
+	  example of this would be a struct device which has just been
+	  unregistered.
+
+	  However, some buggy drivers assume that after such an operation,
+	  the memory backing the kobject can be immediately freed.  This
+	  goes completely against the principles of a refcounted object.
+
+	  If you say Y here, the kernel will delay the release of kobjects
+	  on the last reference count to improve the visibility of this
+	  kind of kobject release bug.
+
 config HAVE_DEBUG_BUGVERBOSE
 	bool
 
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 99fec3a..c37aeac 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -309,7 +309,7 @@ static int ddebug_parse_query(char *words[], int nwords,
 			struct ddebug_query *query, const char *modname)
 {
 	unsigned int i;
-	int rc;
+	int rc = 0;
 
 	/* check we have an even number of words */
 	if (nwords % 2 != 0) {
diff --git a/lib/kobject.c b/lib/kobject.c
index 4a1f33d..1d46c15 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -545,8 +545,8 @@ static void kobject_cleanup(struct kobject *kobj)
 	struct kobj_type *t = get_ktype(kobj);
 	const char *name = kobj->name;
 
-	pr_debug("kobject: '%s' (%p): %s\n",
-		 kobject_name(kobj), kobj, __func__);
+	pr_debug("kobject: '%s' (%p): %s, parent %p\n",
+		 kobject_name(kobj), kobj, __func__, kobj->parent);
 
 	if (t && !t->release)
 		pr_debug("kobject: '%s' (%p): does not have a release() "
@@ -580,9 +580,25 @@ static void kobject_cleanup(struct kobject *kobj)
 	}
 }
 
+#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
+static void kobject_delayed_cleanup(struct work_struct *work)
+{
+	kobject_cleanup(container_of(to_delayed_work(work),
+				     struct kobject, release));
+}
+#endif
+
 static void kobject_release(struct kref *kref)
 {
-	kobject_cleanup(container_of(kref, struct kobject, kref));
+	struct kobject *kobj = container_of(kref, struct kobject, kref);
+#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
+	pr_debug("kobject: '%s' (%p): %s, parent %p (delayed)\n",
+		 kobject_name(kobj), kobj, __func__, kobj->parent);
+	INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
+	schedule_delayed_work(&kobj->release, HZ);
+#else
+	kobject_cleanup(kobj);
+#endif
 }
 
 /**