staging: dwc2: fix potential use after free

dwc2_process_non_isoc_desc() can potentially free the qtd, so null
out the qtd pointer if the call fails so we don't try to access it
later

Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/dwc2/hcd_ddma.c b/drivers/staging/dwc2/hcd_ddma.c
index c7d4345..72e9788 100644 (file)
--- a/drivers/staging/dwc2/hcd_ddma.c
+++ b/drivers/staging/dwc2/hcd_ddma.c
@@ -1103,8 +1103,10 @@ static void dwc2_complete_non_isoc_xfer_ddma(struct dwc2_hsotg *hsotg,
                for (i = 0; i < qtd->n_desc; i++) {
                        if (dwc2_process_non_isoc_desc(hsotg, chan, chnum, qtd,
                                                       desc_num, halt_status,
-                                                      &xfer_done))
+                                                      &xfer_done)) {
+                               qtd = NULL;
                                break;
+                       }
                        desc_num++;
                }
        }