evie/android_kernel_oneplus_msm8998
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usb: gadget: composite: Add spinlock protection for usb string descriptor

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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>
This commit is contained in:
Chandana Kishori Chiluveru 2016-05-04 13:05:40 +05:30
parent bde539edca
commit ca8e442e9f
1 changed files with 2 additions and 0 deletions
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2
drivers/usb/gadget/composite.c
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@ -1670,8 +1670,10 @@ 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;