From 0cd75047de7f54d6fb4aba0ec5818f8194815a5a Mon Sep 17 00:00:00 2001
From: Sergey Klyaus <Sergey.Klyaus@tune-it.ru>
Date: Wed, 8 Oct 2014 11:31:54 +0400
Subject: 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
--- 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);
-- 
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