usb: udc: core: Use lock when write to soft_connect

commit c28095bc99073ddda65e4f31f6ae0d908d4d5cd8 upstream.

Use lock to guard against concurrent access for soft-connect/disconnect
operations when writing to soft_connect sysfs.

Fixes: 2ccea03a8f7e ("usb: gadget: introduce UDC Class")
Cc: stable@vger.kernel.org
Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/338ea01fbd69b1985ef58f0f59af02c805ddf189.1610611437.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index debf542..da691a6 100644 (file)
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -1532,10 +1532,13 @@ static ssize_t soft_connect_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t n)
 {
        struct usb_udc          *udc = container_of(dev, struct usb_udc, dev);
+       ssize_t                 ret;
 
+       mutex_lock(&udc_lock);
        if (!udc->driver) {
                dev_err(dev, "soft-connect without a gadget driver\n");
-               return -EOPNOTSUPP;
+               ret = -EOPNOTSUPP;
+               goto out;
        }
 
        if (sysfs_streq(buf, "connect")) {
@@ -1546,10 +1549,14 @@ static ssize_t soft_connect_store(struct device *dev,
                usb_gadget_udc_stop(udc);
        } else {
                dev_err(dev, "unsupported command '%s'\n", buf);
-               return -EINVAL;
+               ret = -EINVAL;
+               goto out;
        }
 
-       return n;
+       ret = n;
+out:
+       mutex_unlock(&udc_lock);
+       return ret;
 }
 static DEVICE_ATTR_WO(soft_connect);