[PATCH 3.16 070/148] usb: gadget: pch_udc: fix use after free

From: Ben Hutchings
Date: Sat Feb 08 2020 - 13:34:12 EST


3.16.82-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: "Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx>

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")
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20191106202821.GA20347@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/usb/gadget/pch_udc.c | 1 -
1 file changed, 1 deletion(-)

--- a/drivers/usb/gadget/pch_udc.c
+++ b/drivers/usb/gadget/pch_udc.c
@@ -1533,7 +1533,6 @@ static void pch_udc_free_dma_chain(struc
td = phys_to_virt(addr);
addr2 = (dma_addr_t)td->next;
pci_pool_free(dev->data_requests, td, addr);
- td->next = 0x00;
addr = addr2;
}
req->chain_len = 1;