diff mbox

[dpdk-dev,03/10] net/virtio: fix compilation with -Og

Message ID 20170911151333.5727-4-olivier.matz@6wind.com (mailing list archive)
State Accepted, archived
Delegated to: Ferruh Yigit
Headers

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Olivier Matz Sept. 11, 2017, 3:13 p.m. UTC 
  The compilation with gcc-6.3.0 and EXTRA_CFLAGS=-Og gives the following
error:

  CC virtio_rxtx.o
  virtio_rxtx.c: In function ‘virtio_rx_offload’:
  virtio_rxtx.c:680:10: error: ‘csum’ may be used uninitialized in
                        this function [-Werror=maybe-uninitialized]
       csum = ~csum;
       ~~~~~^~~~~~~

The function rte_raw_cksum_mbuf() may indeed return an error, and
in this case, csum won't be initialized. Fix it by initializing csum
to 0.

Fixes: 96cb6711939e ("net/virtio: support Rx checksum offload")
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 drivers/net/virtio/virtio_rxtx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Ferruh Yigit Oct. 5, 2017, 11:17 p.m. UTC | #1 
On 9/11/2017 4:13 PM, Olivier Matz wrote:
> The compilation with gcc-6.3.0 and EXTRA_CFLAGS=-Og gives the following
> error:
> 
>   CC virtio_rxtx.o
>   virtio_rxtx.c: In function ‘virtio_rx_offload’:
>   virtio_rxtx.c:680:10: error: ‘csum’ may be used uninitialized in
>                         this function [-Werror=maybe-uninitialized]
>        csum = ~csum;
>        ~~~~~^~~~~~~
> 
> The function rte_raw_cksum_mbuf() may indeed return an error, and
> in this case, csum won't be initialized. Fix it by initializing csum
> to 0.

After this fix if rte_raw_cksum_mbuf() returns error csum still will be
wrong and since compiler warning suppressed it may be harder to find the
root cause.

For this case checking rte_raw_cksum_mbuf() return value seems better
idea but I will cc the maintainer for decision.

> 
> Fixes: 96cb6711939e ("net/virtio: support Rx checksum offload")
> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> ---
>  drivers/net/virtio/virtio_rxtx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 45a9c919a..cab3a1675 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -671,7 +671,7 @@ virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
>  			 * In case of SCTP, this will be wrong since it's a CRC
>  			 * but there's nothing we can do.
>  			 */
> -			uint16_t csum, off;
> +			uint16_t csum = 0, off;
>  
>  			rte_raw_cksum_mbuf(m, hdr->csum_start,
>  				rte_pktmbuf_pkt_len(m) - hdr->csum_start,
>
Ferruh Yigit Oct. 5, 2017, 11:28 p.m. UTC | #2 
On 10/6/2017 12:17 AM, Ferruh Yigit wrote:
> On 9/11/2017 4:13 PM, Olivier Matz wrote:
>> The compilation with gcc-6.3.0 and EXTRA_CFLAGS=-Og gives the following
>> error:
>>
>>   CC virtio_rxtx.o
>>   virtio_rxtx.c: In function ‘virtio_rx_offload’:
>>   virtio_rxtx.c:680:10: error: ‘csum’ may be used uninitialized in
>>                         this function [-Werror=maybe-uninitialized]
>>        csum = ~csum;
>>        ~~~~~^~~~~~~
>>
>> The function rte_raw_cksum_mbuf() may indeed return an error, and
>> in this case, csum won't be initialized. Fix it by initializing csum
>> to 0.
> 
> After this fix if rte_raw_cksum_mbuf() returns error csum still will be
> wrong and since compiler warning suppressed it may be harder to find the
> root cause.
> 
> For this case checking rte_raw_cksum_mbuf() return value seems better
> idea but I will cc the maintainer for decision.

Trying harder to add maintainer!

> 
>>
>> Fixes: 96cb6711939e ("net/virtio: support Rx checksum offload")
>> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
>> ---
>>  drivers/net/virtio/virtio_rxtx.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
>> index 45a9c919a..cab3a1675 100644
>> --- a/drivers/net/virtio/virtio_rxtx.c
>> +++ b/drivers/net/virtio/virtio_rxtx.c
>> @@ -671,7 +671,7 @@ virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
>>  			 * In case of SCTP, this will be wrong since it's a CRC
>>  			 * but there's nothing we can do.
>>  			 */
>> -			uint16_t csum, off;
>> +			uint16_t csum = 0, off;
>>  
>>  			rte_raw_cksum_mbuf(m, hdr->csum_start,
>>  				rte_pktmbuf_pkt_len(m) - hdr->csum_start,
>>
>
Maxime Coquelin Oct. 6, 2017, 6:43 a.m. UTC | #3 
On 09/11/2017 05:13 PM, Olivier Matz wrote:
> The compilation with gcc-6.3.0 and EXTRA_CFLAGS=-Og gives the following
> error:
> 
>    CC virtio_rxtx.o
>    virtio_rxtx.c: In function ‘virtio_rx_offload’:
>    virtio_rxtx.c:680:10: error: ‘csum’ may be used uninitialized in
>                          this function [-Werror=maybe-uninitialized]
>         csum = ~csum;
>         ~~~~~^~~~~~~
> 
> The function rte_raw_cksum_mbuf() may indeed return an error, and
> in this case, csum won't be initialized. Fix it by initializing csum
> to 0.
> 
> Fixes: 96cb6711939e ("net/virtio: support Rx checksum offload")
> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> ---
>   drivers/net/virtio/virtio_rxtx.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 45a9c919a..cab3a1675 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -671,7 +671,7 @@ virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
>   			 * In case of SCTP, this will be wrong since it's a CRC
>   			 * but there's nothing we can do.
>   			 */
> -			uint16_t csum, off;
> +			uint16_t csum = 0, off;
>   
>   			rte_raw_cksum_mbuf(m, hdr->csum_start,
>   				rte_pktmbuf_pkt_len(m) - hdr->csum_start,
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime
Ferruh Yigit Oct. 6, 2017, 6:43 p.m. UTC | #4 
On 10/6/2017 7:43 AM, Maxime Coquelin wrote:
> 
> 
> On 09/11/2017 05:13 PM, Olivier Matz wrote:
>> The compilation with gcc-6.3.0 and EXTRA_CFLAGS=-Og gives the following
>> error:
>>
>>    CC virtio_rxtx.o
>>    virtio_rxtx.c: In function ‘virtio_rx_offload’:
>>    virtio_rxtx.c:680:10: error: ‘csum’ may be used uninitialized in
>>                          this function [-Werror=maybe-uninitialized]
>>         csum = ~csum;
>>         ~~~~~^~~~~~~
>>
>> The function rte_raw_cksum_mbuf() may indeed return an error, and
>> in this case, csum won't be initialized. Fix it by initializing csum
>> to 0.
>>
>> Fixes: 96cb6711939e ("net/virtio: support Rx checksum offload")
>> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>

> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Applied to dpdk-next-net/master, thanks.
diff mbox

Patch

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 45a9c919a..cab3a1675 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -671,7 +671,7 @@  virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
 			 * In case of SCTP, this will be wrong since it's a CRC
 			 * but there's nothing we can do.
 			 */
-			uint16_t csum, off;
+			uint16_t csum = 0, off;
 
 			rte_raw_cksum_mbuf(m, hdr->csum_start,
 				rte_pktmbuf_pkt_len(m) - hdr->csum_start,