On 28/03/17 13:51, Felipe Balbi wrote:
>
> Hi,
>
> Colin King <colin.king@xxxxxxxxxxxxx> writes:
>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>
>> Writing to td->next should be avoided after td has been freed using
>> dma_pool_free. The intent was to nullify the next pointer, but this
>> is potentially dangerous once it is back in the pool. Remove it.
>>
>> Detected by CoverityScan, CID#1091173 ("Write tp pointer after free")
>>
>> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>> ---
>> drivers/usb/gadget/udc/pch_udc.c | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/drivers/usb/gadget/udc/pch_udc.c b/drivers/usb/gadget/udc/pch_udc.c
>> index 84dcbcd756f0..08bbe2c24134 100644
>> --- a/drivers/usb/gadget/udc/pch_udc.c
>> +++ b/drivers/usb/gadget/udc/pch_udc.c
>> @@ -1523,7 +1523,6 @@ 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;
>
> I already have a patch for this, thanks
Ah, I somehow overlooked that. Good to see it is fixed.
Colin
>
> 1f459262b0e1649a1e5ad12fa4c66eb76c2220ce
> Author: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
> AuthorDate: Fri Mar 10 15:39:32 2017 -0600
> Commit: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
> CommitDate: Wed Mar 22 11:21:10 2017 +0200
>
> usb: gadget: udc: remove pointer dereference after free
>
> Remove pointer dereference after free.
>
> Addresses-Coverity-ID: 1091173
> Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
> Signed-off-by: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
> Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
>
> 1 file changed, 1 deletion(-)
> drivers/usb/gadget/udc/pch_udc.c | 1 -
>
> modified drivers/usb/gadget/udc/pch_udc.c
> @@ -1523,7 +1523,6 @@ static void pch_udc_free_dma_chain(struct pch_udc_dev *dev,
> 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;
>
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