829 if (request->complete) { 830 spin_unlock(&priv_dev->lock); 831 usb_gadget_giveback_request(&priv_ep->endpoint, 832 request); 833 spin_lock(&priv_dev->lock); 834 } 835 836 if (request->buf == priv_dev->zlp_buf) 837 cdns3_gadget_ep_free_request(&priv_ep->endpoint, request); Driver append an additional zero packet request when queue a packet, which length mod max packet size is 0. When transfer complete, run to line 831, usb_gadget_giveback_request() will free this requestion. 836 condition is true, so cdns3_gadget_ep_free_request() free this request again. Log: [ 1920.140696][ T150] BUG: KFENCE: use-after-free read in cdns3_gadget_giveback+0x134/0x2c0 [cdns3] [ 1920.140696][ T150] [ 1920.151837][ T150] Use-after-free read at 0x000000003d1cd10b (in kfence-#36): [ 1920.159082][ T150] cdns3_gadget_giveback+0x134/0x2c0 [cdns3] [ 1920.164988][ T150] cdns3_transfer_completed+0x438/0x5f8 [cdns3] Add check at line 829, skip call usb_gadget_giveback_request() if it is additional zero length packet request. Needn't call usb_gadget_giveback_request() because it is allocated in this driver. Cc: <stable@xxxxxxxxxxxxxxx> Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver") Signed-off-by: Frank Li <Frank.Li@xxxxxxx> --- drivers/usb/cdns3/cdns3-gadget.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c index d6723d31fc6e2..fd1beb10bba72 100644 --- a/drivers/usb/cdns3/cdns3-gadget.c +++ b/drivers/usb/cdns3/cdns3-gadget.c @@ -828,7 +828,11 @@ void cdns3_gadget_giveback(struct cdns3_endpoint *priv_ep, return; } - if (request->complete) { + /* + * zlp request is appended by driver, needn't call usb_gadget_giveback_request() to notify + * gadget composite driver. + */ + if (request->complete && request->buf != priv_dev->zlp_buf) { spin_unlock(&priv_dev->lock); usb_gadget_giveback_request(&priv_ep->endpoint, request); -- 2.34.1