linux-kernel - [PATCH v2] usb: gadget: udc: remove pointer dereference after free

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Date:   Sat, 11 Feb 2017 11:07:31 -0600
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     gregkh@...uxfoundation.org, balbi@...nel.org,
        heikki.krogerus@...ux.intel.com, mail@...oabal.eu,
        mina86@...a86.com, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Peter Senna Tschudin <peter.senna@...il.com>
Subject: [PATCH v2] usb: gadget: udc: remove pointer dereference after free


Remove pointer dereference after free and set pointer to NULL after free.

Addresses-Coverity-ID: 1091173
Signed-off-by: Gustavo A. R. Silva <garsilva@...eddedor.com>
---
Changes in v2:
  Move pointer dereference before pci_pool_free()
  Set pointer to NULL after free

  drivers/usb/gadget/udc/pch_udc.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/udc/pch_udc.c  
b/drivers/usb/gadget/udc/pch_udc.c
index a97da64..73bb58f 100644
--- a/drivers/usb/gadget/udc/pch_udc.c
+++ b/drivers/usb/gadget/udc/pch_udc.c
@@ -1522,8 +1522,9 @@ static void pch_udc_free_dma_chain(struct  
pch_udc_dev *dev,
  		/* do not free first desc., will be done by free for request */
  		td = phys_to_virt(addr);
  		addr2 = (dma_addr_t)td->next;
-		pci_pool_free(dev->data_requests, td, addr);
  		td->next = 0x00;
+		pci_pool_free(dev->data_requests, td, addr);
+		td = NULL;
  		addr = addr2;
  	}
  	req->chain_len = 1;
-- 
2.5.0