From: Benoit Goby <benoit@android.com>
Date: Wed, 16 May 2012 03:44:33 +0000 (-0700)
Subject: usb: gadget: composite: Fix corruption when changing configuration
X-Git-Tag: firefly_0821_release~4090^2~741
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5c5f9b601a5e1926cd9adea28d309c08b659e852;p=firefly-linux-kernel-4.4.55.git

usb: gadget: composite: Fix corruption when changing configuration

Remove the config from the configs list before releasing the spinlock.
Otherwise the other cpu might be processing a SET_CONFIGURATION that
will switch to the configuration that is being released.

Change-Id: Id4da0d0e18ead63e20cb236cd1d3e8e6d116acce
Signed-off-by: Benoit Goby <benoit@android.com>
---

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 55f4df60f327..f9e397556669 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -811,7 +811,7 @@ done:
 }
 EXPORT_SYMBOL_GPL(usb_add_config);
 
-static void remove_config(struct usb_composite_dev *cdev,
+static void unbind_config(struct usb_composite_dev *cdev,
 			      struct usb_configuration *config)
 {
 	while (!list_empty(&config->functions)) {
@@ -826,7 +826,6 @@ static void remove_config(struct usb_composite_dev *cdev,
 			/* may free memory for "f" */
 		}
 	}
-	list_del(&config->list);
 	if (config->unbind) {
 		DBG(cdev, "unbind config '%s'/%p\n", config->label, config);
 		config->unbind(config);
@@ -853,9 +852,11 @@ void usb_remove_config(struct usb_composite_dev *cdev,
 	if (cdev->config == config)
 		reset_config(cdev);
 
+	list_del(&config->list);
+
 	spin_unlock_irqrestore(&cdev->lock, flags);
 
-	remove_config(cdev, config);
+	unbind_config(cdev, config);
 }
 
 /*-------------------------------------------------------------------------*/
@@ -1524,7 +1525,8 @@ static void __composite_unbind(struct usb_gadget *gadget, bool unbind_driver)
 		struct usb_configuration	*c;
 		c = list_first_entry(&cdev->configs,
 				struct usb_configuration, list);
-		remove_config(cdev, c);
+		list_del(&c->list);
+		unbind_config(cdev, c);
 	}
 	if (cdev->driver->unbind && unbind_driver)
 		cdev->driver->unbind(cdev);