The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c28095bc99073ddda65e4f31f6ae0d908d4d5cd8 Mon Sep 17 00:00:00 2001

From: Thinh Nguyen Thinh.Nguyen@synopsys.com Date: Thu, 14 Jan 2021 00:09:51 -0800 Subject: [PATCH] usb: udc: core: Use lock when write to soft_connect

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/338ea01fbd69b1985ef58f0f59af02c805ddf189.161061143... 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 6a62bbd01324..ea114f922ccf 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -1529,10 +1529,13 @@ 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")) { @@ -1543,10 +1546,14 @@ 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);