Commit 7d09293d authored May 04, 2016 by Chandana Kishori Chiluveru Committed by Gerrit - the friendly Code Review server May 04, 2016

usb: gadget: composite: Add spinlock protection for usb string descriptor

During composition switch, android driver stops data transfers first
and removes configuration before disabling the pullup. With this sequence
there is a possibility for a race where usb_remove_config is in progress
during which pullup is active and sending the setup request for strings
with zero configuration value. Hence fix the issue by adding spinlock
protection for get_sring descriptor.

Change-Id: I13c601f0e48d847b322a2761cd52268963cacf01
Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>

parent b2b64139

drivers/usb/gadget/composite.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1675,8 +1675,10 @@ composite_setup(struct usb_gadget gadget, const struct usb_ctrlrequest ctrl)
		value = min(w_length, (u16) value);
		break;
		case USB_DT_STRING:
		spin_lock(&cdev->lock);
		value = get_string(cdev, req->buf,
		w_index, w_value & 0xff);
		spin_unlock(&cdev->lock);
		if (value >= 0)
		value = min(w_length, (u16) value);
		break;