driver core: fix race with userland in device_add()

bus_add_device() should be called before devtmpfs_create_node(), so when
userland application opens device from devtmpfs, it wouldn't get ENODEV
from kernel, because device_add() wasn't completed.

Signed-off-by: Sergey Klyaus <Sergey.Klyaus@Tune-IT.Ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 14d1629..00ec7ce 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1019,18 +1019,6 @@ int device_add(struct device *dev)
        if (error)
                goto attrError;
 
-       if (MAJOR(dev->devt)) {
-               error = device_create_file(dev, &dev_attr_dev);
-               if (error)
-                       goto ueventattrError;
-
-               error = device_create_sys_dev_entry(dev);
-               if (error)
-                       goto devtattrError;
-
-               devtmpfs_create_node(dev);
-       }
-
        error = device_add_class_symlinks(dev);
        if (error)
                goto SymlinkError;
@@ -1045,6 +1033,18 @@ int device_add(struct device *dev)
                goto DPMError;
        device_pm_add(dev);
 
+       if (MAJOR(dev->devt)) {
+               error = device_create_file(dev, &dev_attr_dev);
+               if (error)
+                       goto DevAttrError;
+
+               error = device_create_sys_dev_entry(dev);
+               if (error)
+                       goto SysEntryError;
+
+               devtmpfs_create_node(dev);
+       }
+
        /* Notify clients of device addition.  This call must come
         * after dpm_sysfs_add() and before kobject_uevent().
         */
@@ -1074,6 +1074,12 @@ int device_add(struct device *dev)
 done:
        put_device(dev);
        return error;
+ SysEntryError:
+       if (MAJOR(dev->devt))
+               device_remove_file(dev, &dev_attr_dev);
+ DevAttrError:
+       device_pm_remove(dev);
+       dpm_sysfs_remove(dev);
  DPMError:
        bus_remove_device(dev);
  BusError:
@@ -1081,14 +1087,6 @@ done:
  AttrsError:
        device_remove_class_symlinks(dev);
  SymlinkError:
-       if (MAJOR(dev->devt))
-               devtmpfs_delete_node(dev);
-       if (MAJOR(dev->devt))
-               device_remove_sys_dev_entry(dev);
- devtattrError:
-       if (MAJOR(dev->devt))
-               device_remove_file(dev, &dev_attr_dev);
- ueventattrError:
        device_remove_file(dev, &dev_attr_uevent);
  attrError:
        kobject_uevent(&dev->kobj, KOBJ_REMOVE);