usb: gadget: pch_udc: fix use after free

BugLink: https://bugs.launchpad.net/bugs/1857158
commit 66d1b0c0580b7f1b1850ee4423f32ac42afa2e92 upstream.

Remove pointer dereference after free.

pci_pool_free doesn't care about contents of td.
It's just a void* for it

Addresses-Coverity-ID: 1091173 ("Use after free")
Cc: stable@vger.kernel.org
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20191106202821.GA20347@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/usb/gadget/udc/pch_udc.c b/drivers/usb/gadget/udc/pch_udc.c
index afaea11ec7719c3350080f010777a3d0f81ef925..991184b8bb41ebd7b43e83550f0f7bb8254fe390 100644 (file)
--- a/drivers/usb/gadget/udc/pch_udc.c
+++ b/drivers/usb/gadget/udc/pch_udc.c
@@ -1520,7 +1520,6 @@ static void pch_udc_free_dma_chain(struct pch_udc_dev *dev,
                td = phys_to_virt(addr);
                addr2 = (dma_addr_t)td->next;
                dma_pool_free(dev->data_requests, td, addr);
-               td->next = 0x00;
                addr = addr2;
        }
        req->chain_len = 1;