[dpdk-dev] [PATCH] net/thunderx: fix build with gcc optimization on

[dpdk-dev] [PATCH] net/thunderx: fix build with gcc optimization on

[Ferruh Yigit]

build error gcc version 6.3.1 20161221 (Red Hat 6.3.1-1),
with EXTRA_CFLAGS="-O3":

.../drivers/net/thunderx/nicvf_ethdev.c:907:9:
   error: ‘txq’ may be used uninitialized in this function
   [-Werror=maybe-uninitialized]
  if (txq->pool_free == nicvf_single_pool_free_xmited_buffers)
      ~~~^~~~~~~~~~~
.../drivers/net/thunderx/nicvf_ethdev.c:886:20:
   note: ‘txq’ was declared here
  struct nicvf_txq *txq;
                    ^~~

Same error on function 'nicvf_eth_dev_init' and 'nicvf_dev_start', it
seems 'nicvf_set_tx_function' inlined when optimization enabled.

Initialize the txq and add NULL check before using it to fix.

Fixes: 7413feee662d ("net/thunderx: add device start/stop and close")
Cc: stable@dpdk.org

Reported-by: Richard Walsh <richard.walsh@intel.com>
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---

Btw, no compiler optimization enabled, only nicvf_rxtx.c has -Ofast,
is this intentional?
---
 drivers/net/thunderx/nicvf_ethdev.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/thunderx/nicvf_ethdev.c b/drivers/net/thunderx/nicvf_ethdev.c
index 99fcd516b..4ab1bfbe6 100644
--- a/drivers/net/thunderx/nicvf_ethdev.c
+++ b/drivers/net/thunderx/nicvf_ethdev.c
@@ -883,7 +883,7 @@ nicvf_dev_tx_queue_release(void *sq)
 static void
 nicvf_set_tx_function(struct rte_eth_dev *dev)
 {
-	struct nicvf_txq *txq;
+	struct nicvf_txq *txq = NULL;
 	size_t i;
 	bool multiseg = false;
 
@@ -904,6 +904,9 @@ nicvf_set_tx_function(struct rte_eth_dev *dev)
 		dev->tx_pkt_burst = nicvf_xmit_pkts;
 	}
 
+	if (!txq)
+		return;
+
 	if (txq->pool_free == nicvf_single_pool_free_xmited_buffers)
 		PMD_DRV_LOG(DEBUG, "Using single-mempool tx free method");
 	else
-- 
2.17.1

Re: [dpdk-dev] [PATCH] net/thunderx: fix build with gcc optimization on

[Jerin Jacob]

-----Original Message-----
> Date: Thu, 21 Jun 2018 19:14:50 +0100
> From: Ferruh Yigit <ferruh.yigit@intel.com>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, Maciej Czekaj
>  <maciej.czekaj@caviumnetworks.com>
> CC: dev@dpdk.org, Ferruh Yigit <ferruh.yigit@intel.com>, stable@dpdk.org
> Subject: [PATCH] net/thunderx: fix build with gcc optimization on
> X-Mailer: git-send-email 2.17.1
> 
> 
> build error gcc version 6.3.1 20161221 (Red Hat 6.3.1-1),
> with EXTRA_CFLAGS="-O3":
> 
> .../drivers/net/thunderx/nicvf_ethdev.c:907:9:
>    error: ‘txq’ may be used uninitialized in this function
>    [-Werror=maybe-uninitialized]
>   if (txq->pool_free == nicvf_single_pool_free_xmited_buffers)
>       ~~~^~~~~~~~~~~
> .../drivers/net/thunderx/nicvf_ethdev.c:886:20:
>    note: ‘txq’ was declared here
>   struct nicvf_txq *txq;
>                     ^~~
> 
> Same error on function 'nicvf_eth_dev_init' and 'nicvf_dev_start', it
> seems 'nicvf_set_tx_function' inlined when optimization enabled.
> 
> Initialize the txq and add NULL check before using it to fix.
> 
> Fixes: 7413feee662d ("net/thunderx: add device start/stop and close")
> Cc: stable@dpdk.org
> 
> Reported-by: Richard Walsh <richard.walsh@intel.com>
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>

Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>

> ---
> 
> Btw, no compiler optimization enabled, only nicvf_rxtx.c has -Ofast,
> is this intentional?

Yes. At least in our setup, -Ofast turns out to be super set of -O3.

Re: [dpdk-dev] [PATCH] net/thunderx: fix build with gcc optimization on

[Ferruh Yigit]

On 6/24/2018 1:17 PM, Jerin Jacob wrote:
> -----Original Message-----
>> Date: Thu, 21 Jun 2018 19:14:50 +0100
>> From: Ferruh Yigit <ferruh.yigit@intel.com>
>> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, Maciej Czekaj
>>  <maciej.czekaj@caviumnetworks.com>
>> CC: dev@dpdk.org, Ferruh Yigit <ferruh.yigit@intel.com>, stable@dpdk.org
>> Subject: [PATCH] net/thunderx: fix build with gcc optimization on
>> X-Mailer: git-send-email 2.17.1
>>
>>
>> build error gcc version 6.3.1 20161221 (Red Hat 6.3.1-1),
>> with EXTRA_CFLAGS="-O3":
>>
>> .../drivers/net/thunderx/nicvf_ethdev.c:907:9:
>>    error: ‘txq’ may be used uninitialized in this function
>>    [-Werror=maybe-uninitialized]
>>   if (txq->pool_free == nicvf_single_pool_free_xmited_buffers)
>>       ~~~^~~~~~~~~~~
>> .../drivers/net/thunderx/nicvf_ethdev.c:886:20:
>>    note: ‘txq’ was declared here
>>   struct nicvf_txq *txq;
>>                     ^~~
>>
>> Same error on function 'nicvf_eth_dev_init' and 'nicvf_dev_start', it
>> seems 'nicvf_set_tx_function' inlined when optimization enabled.
>>
>> Initialize the txq and add NULL check before using it to fix.
>>
>> Fixes: 7413feee662d ("net/thunderx: add device start/stop and close")
>> Cc: stable@dpdk.org
>>
>> Reported-by: Richard Walsh <richard.walsh@intel.com>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> 
> Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> 
>> ---
>>
>> Btw, no compiler optimization enabled, only nicvf_rxtx.c has -Ofast,
>> is this intentional?
> 
> Yes. At least in our setup, -Ofast turns out to be super set of -O3.

That is what gcc documents about -Ofast, but again it is only for single
nicvf_rxtx.c file. The problem seen with -O3 case with other file.

Re: [dpdk-dev] [PATCH] net/thunderx: fix build with gcc optimization on

[Jerin Jacob]

-----Original Message-----
> Date: Tue, 26 Jun 2018 10:17:14 +0100
> From: Ferruh Yigit <ferruh.yigit@intel.com>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> CC: Maciej Czekaj <maciej.czekaj@caviumnetworks.com>, dev@dpdk.org,
>  stable@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] net/thunderx: fix build with gcc
>  optimization on
> User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101
>  Thunderbird/52.8.0
> 
> 
> On 6/24/2018 1:17 PM, Jerin Jacob wrote:
> > -----Original Message-----
> >> Date: Thu, 21 Jun 2018 19:14:50 +0100
> >> From: Ferruh Yigit <ferruh.yigit@intel.com>
> >> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, Maciej Czekaj
> >>  <maciej.czekaj@caviumnetworks.com>
> >> CC: dev@dpdk.org, Ferruh Yigit <ferruh.yigit@intel.com>, stable@dpdk.org
> >> Subject: [PATCH] net/thunderx: fix build with gcc optimization on
> >> X-Mailer: git-send-email 2.17.1
> >>
> >>
> >> build error gcc version 6.3.1 20161221 (Red Hat 6.3.1-1),
> >> with EXTRA_CFLAGS="-O3":
> >>
> >> .../drivers/net/thunderx/nicvf_ethdev.c:907:9:
> >>    error: ‘txq’ may be used uninitialized in this function
> >>    [-Werror=maybe-uninitialized]
> >>   if (txq->pool_free == nicvf_single_pool_free_xmited_buffers)
> >>       ~~~^~~~~~~~~~~
> >> .../drivers/net/thunderx/nicvf_ethdev.c:886:20:
> >>    note: ‘txq’ was declared here
> >>   struct nicvf_txq *txq;
> >>                     ^~~
> >>
> >> Same error on function 'nicvf_eth_dev_init' and 'nicvf_dev_start', it
> >> seems 'nicvf_set_tx_function' inlined when optimization enabled.
> >>
> >> Initialize the txq and add NULL check before using it to fix.
> >>
> >> Fixes: 7413feee662d ("net/thunderx: add device start/stop and close")
> >> Cc: stable@dpdk.org
> >>
> >> Reported-by: Richard Walsh <richard.walsh@intel.com>
> >> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> >
> > Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> >
> >> ---
> >>
> >> Btw, no compiler optimization enabled, only nicvf_rxtx.c has -Ofast,
> >> is this intentional?
> >
> > Yes. At least in our setup, -Ofast turns out to be super set of -O3.
> 
> That is what gcc documents about -Ofast, but again it is only for single
> nicvf_rxtx.c file. The problem seen with -O3 case with other file.

OK. For other files, we intentionally kept non -03 as it is in slow path.

> 

Re: [dpdk-dev] [PATCH] net/thunderx: fix build with gcc optimization on

[Ferruh Yigit]

On 6/24/2018 1:17 PM, Jerin Jacob wrote:
> -----Original Message-----
>> Date: Thu, 21 Jun 2018 19:14:50 +0100
>> From: Ferruh Yigit <ferruh.yigit@intel.com>
>> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, Maciej Czekaj
>>  <maciej.czekaj@caviumnetworks.com>
>> CC: dev@dpdk.org, Ferruh Yigit <ferruh.yigit@intel.com>, stable@dpdk.org
>> Subject: [PATCH] net/thunderx: fix build with gcc optimization on
>> X-Mailer: git-send-email 2.17.1
>>
>>
>> build error gcc version 6.3.1 20161221 (Red Hat 6.3.1-1),
>> with EXTRA_CFLAGS="-O3":
>>
>> .../drivers/net/thunderx/nicvf_ethdev.c:907:9:
>>    error: ‘txq’ may be used uninitialized in this function
>>    [-Werror=maybe-uninitialized]
>>   if (txq->pool_free == nicvf_single_pool_free_xmited_buffers)
>>       ~~~^~~~~~~~~~~
>> .../drivers/net/thunderx/nicvf_ethdev.c:886:20:
>>    note: ‘txq’ was declared here
>>   struct nicvf_txq *txq;
>>                     ^~~
>>
>> Same error on function 'nicvf_eth_dev_init' and 'nicvf_dev_start', it
>> seems 'nicvf_set_tx_function' inlined when optimization enabled.
>>
>> Initialize the txq and add NULL check before using it to fix.
>>
>> Fixes: 7413feee662d ("net/thunderx: add device start/stop and close")
>> Cc: stable@dpdk.org
>>
>> Reported-by: Richard Walsh <richard.walsh@intel.com>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> 
> Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>

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