[dpdk-dev] [PATCH] hash: fix gcc 10 maybe-uninitialized warning

[dpdk-dev] [PATCH] hash: fix gcc 10 maybe-uninitialized warning

[Kevin Traynor]

gcc 10.1.1 reports a warning for the ext_bkt_id variable:

../lib/librte_hash/rte_cuckoo_hash.c:
In function ‘__rte_hash_add_key_with_hash’:
../lib/librte_hash/rte_cuckoo_hash.c:1104:29:
warning: ‘ext_bkt_id’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
 1104 |  (h->buckets_ext[ext_bkt_id - 1]).sig_current[0] = short_sig;
      |                  ~~~~~~~~~~~^~~

The return value of rte_ring_sc_dequeue_elem() is already checked,
but also initialize ext_bkt_id to zero (invalid value) and check
that it also overwritten.

Fixes: fbfe568103b0 ("hash: use 32-bit elements rings to save memory")
Cc: stable@dpdk.org

Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
---
 lib/librte_hash/rte_cuckoo_hash.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c
index 38767a8a1..90cb99b0e 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -940,6 +940,6 @@ __rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
 	struct rte_hash_bucket *prim_bkt, *sec_bkt, *cur_bkt;
 	struct rte_hash_key *new_k, *keys = h->key_store;
+	uint32_t ext_bkt_id = 0;
 	uint32_t slot_id;
-	uint32_t ext_bkt_id;
 	int ret;
 	unsigned n_slots;
@@ -1096,5 +1096,6 @@ __rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
 	 */
 	if (rte_ring_sc_dequeue_elem(h->free_ext_bkts, &ext_bkt_id,
-						sizeof(uint32_t)) != 0) {
+						sizeof(uint32_t)) != 0 ||
+					ext_bkt_id == 0) {
 		ret = -ENOSPC;
 		goto failure;
-- 
2.21.3

Re: [dpdk-dev] [PATCH] hash: fix gcc 10 maybe-uninitialized warning

[Wang, Yipeng1]

> -----Original Message-----
> From: Kevin Traynor <ktraynor@redhat.com>
> Sent: Friday, May 15, 2020 7:28 AM
> To: dev@dpdk.org; Wang, Yipeng1 <yipeng1.wang@intel.com>; Gobriel,
> Sameh <sameh.gobriel@intel.com>; Richardson, Bruce
> <bruce.richardson@intel.com>
> Cc: honnappa.nagarahalli@arm.com; Yigit, Ferruh <ferruh.yigit@intel.com>;
> david.marchand@redhat.com; Kevin Traynor <ktraynor@redhat.com>;
> stable@dpdk.org
> Subject: [PATCH] hash: fix gcc 10 maybe-uninitialized warning
> 
> gcc 10.1.1 reports a warning for the ext_bkt_id variable:
> 
> ../lib/librte_hash/rte_cuckoo_hash.c:
> In function ‘__rte_hash_add_key_with_hash’:
> ../lib/librte_hash/rte_cuckoo_hash.c:1104:29:
> warning: ‘ext_bkt_id’ may be used uninitialized in this function [-Wmaybe-
> uninitialized]
>  1104 |  (h->buckets_ext[ext_bkt_id - 1]).sig_current[0] = short_sig;
>       |                  ~~~~~~~~~~~^~~
> 
> The return value of rte_ring_sc_dequeue_elem() is already checked, but
> also initialize ext_bkt_id to zero (invalid value) and check that it also
> overwritten.
> 
> Fixes: fbfe568103b0 ("hash: use 32-bit elements rings to save memory")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
> ---
>  lib/librte_hash/rte_cuckoo_hash.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_hash/rte_cuckoo_hash.c
> b/lib/librte_hash/rte_cuckoo_hash.c
> index 38767a8a1..90cb99b0e 100644
> --- a/lib/librte_hash/rte_cuckoo_hash.c
> +++ b/lib/librte_hash/rte_cuckoo_hash.c
> @@ -940,6 +940,6 @@ __rte_hash_add_key_with_hash(const struct
> rte_hash *h, const void *key,
>  	struct rte_hash_bucket *prim_bkt, *sec_bkt, *cur_bkt;
>  	struct rte_hash_key *new_k, *keys = h->key_store;
> +	uint32_t ext_bkt_id = 0;
>  	uint32_t slot_id;
> -	uint32_t ext_bkt_id;
>  	int ret;
>  	unsigned n_slots;
> @@ -1096,5 +1096,6 @@ __rte_hash_add_key_with_hash(const struct
> rte_hash *h, const void *key,
>  	 */
>  	if (rte_ring_sc_dequeue_elem(h->free_ext_bkts, &ext_bkt_id,
> -						sizeof(uint32_t)) != 0) {
> +						sizeof(uint32_t)) != 0 ||
> +					ext_bkt_id == 0) {
[Wang, Yipeng] 
If convenient, it would be better to make the two lines aligned with same indent...

>  		ret = -ENOSPC;
>  		goto failure;
> --
> 2.21.3
[Wang, Yipeng] 
Thanks for the fix. I think It is also better code in general.

Acked-by: Yipeng Wang <yipeng1.wang@intel.com>

Re: [dpdk-dev] [PATCH] hash: fix gcc 10 maybe-uninitialized warning

[Kevin Traynor]

On 15/05/2020 20:06, Wang, Yipeng1 wrote:
>> -----Original Message-----
>> From: Kevin Traynor <ktraynor@redhat.com>
>> Sent: Friday, May 15, 2020 7:28 AM
>> To: dev@dpdk.org; Wang, Yipeng1 <yipeng1.wang@intel.com>; Gobriel,
>> Sameh <sameh.gobriel@intel.com>; Richardson, Bruce
>> <bruce.richardson@intel.com>
>> Cc: honnappa.nagarahalli@arm.com; Yigit, Ferruh <ferruh.yigit@intel.com>;
>> david.marchand@redhat.com; Kevin Traynor <ktraynor@redhat.com>;
>> stable@dpdk.org
>> Subject: [PATCH] hash: fix gcc 10 maybe-uninitialized warning
>>
>> gcc 10.1.1 reports a warning for the ext_bkt_id variable:
>>
>> ../lib/librte_hash/rte_cuckoo_hash.c:
>> In function ‘__rte_hash_add_key_with_hash’:
>> ../lib/librte_hash/rte_cuckoo_hash.c:1104:29:
>> warning: ‘ext_bkt_id’ may be used uninitialized in this function [-Wmaybe-
>> uninitialized]
>>  1104 |  (h->buckets_ext[ext_bkt_id - 1]).sig_current[0] = short_sig;
>>       |                  ~~~~~~~~~~~^~~
>>
>> The return value of rte_ring_sc_dequeue_elem() is already checked, but
>> also initialize ext_bkt_id to zero (invalid value) and check that it also
>> overwritten.
>>
>> Fixes: fbfe568103b0 ("hash: use 32-bit elements rings to save memory")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
>> ---
>>  lib/librte_hash/rte_cuckoo_hash.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/librte_hash/rte_cuckoo_hash.c
>> b/lib/librte_hash/rte_cuckoo_hash.c
>> index 38767a8a1..90cb99b0e 100644
>> --- a/lib/librte_hash/rte_cuckoo_hash.c
>> +++ b/lib/librte_hash/rte_cuckoo_hash.c
>> @@ -940,6 +940,6 @@ __rte_hash_add_key_with_hash(const struct
>> rte_hash *h, const void *key,
>>  	struct rte_hash_bucket *prim_bkt, *sec_bkt, *cur_bkt;
>>  	struct rte_hash_key *new_k, *keys = h->key_store;
>> +	uint32_t ext_bkt_id = 0;
>>  	uint32_t slot_id;
>> -	uint32_t ext_bkt_id;
>>  	int ret;
>>  	unsigned n_slots;
>> @@ -1096,5 +1096,6 @@ __rte_hash_add_key_with_hash(const struct
>> rte_hash *h, const void *key,
>>  	 */
>>  	if (rte_ring_sc_dequeue_elem(h->free_ext_bkts, &ext_bkt_id,
>> -						sizeof(uint32_t)) != 0) {
>> +						sizeof(uint32_t)) != 0 ||
>> +					ext_bkt_id == 0) {
> [Wang, Yipeng] 
> If convenient, it would be better to make the two lines aligned with same indent...
> 

Hi Yipeng, I had checked the coding style [1] about this and I think
it's correct as 'sizeof..' is a wrap from the first condition so gets a
second tab to indicate that, whereas 'ext_bkt_id..' is the second
condition with no wrap. Fine to change it, if I interpret incorrectly.

[1] third bullet,
http://doc.dpdk.org/guides/contributing/coding_style.html#general

>>  		ret = -ENOSPC;
>>  		goto failure;
>> --
>> 2.21.3
> [Wang, Yipeng] 
> Thanks for the fix. I think It is also better code in general.
> 
> Acked-by: Yipeng Wang <yipeng1.wang@intel.com>
> 

Re: [dpdk-dev] [PATCH] hash: fix gcc 10 maybe-uninitialized warning

[Wang, Yipeng1]

> -----Original Message-----
> From: Kevin Traynor <ktraynor@redhat.com>
> Sent: Friday, May 15, 2020 12:18 PM
> To: Wang, Yipeng1 <yipeng1.wang@intel.com>; dev@dpdk.org; Gobriel,
> Sameh <sameh.gobriel@intel.com>; Richardson, Bruce
> <bruce.richardson@intel.com>
> Cc: honnappa.nagarahalli@arm.com; Yigit, Ferruh <ferruh.yigit@intel.com>;
> david.marchand@redhat.com; stable@dpdk.org
> Subject: Re: [PATCH] hash: fix gcc 10 maybe-uninitialized warning
> 
> On 15/05/2020 20:06, Wang, Yipeng1 wrote:
> >> -----Original Message-----
> >> From: Kevin Traynor <ktraynor@redhat.com>
> >> Sent: Friday, May 15, 2020 7:28 AM
> >> To: dev@dpdk.org; Wang, Yipeng1 <yipeng1.wang@intel.com>; Gobriel,
> >> Sameh <sameh.gobriel@intel.com>; Richardson, Bruce
> >> <bruce.richardson@intel.com>
> >> Cc: honnappa.nagarahalli@arm.com; Yigit, Ferruh
> >> <ferruh.yigit@intel.com>; david.marchand@redhat.com; Kevin Traynor
> >> <ktraynor@redhat.com>; stable@dpdk.org
> >> Subject: [PATCH] hash: fix gcc 10 maybe-uninitialized warning
> >>
> >> gcc 10.1.1 reports a warning for the ext_bkt_id variable:
> >>
> >> ../lib/librte_hash/rte_cuckoo_hash.c:
> >> In function ‘__rte_hash_add_key_with_hash’:
> >> ../lib/librte_hash/rte_cuckoo_hash.c:1104:29:
> >> warning: ‘ext_bkt_id’ may be used uninitialized in this function
> >> [-Wmaybe- uninitialized]
> >>  1104 |  (h->buckets_ext[ext_bkt_id - 1]).sig_current[0] = short_sig;
> >>       |                  ~~~~~~~~~~~^~~
> >>
> >> The return value of rte_ring_sc_dequeue_elem() is already checked,
> >> but also initialize ext_bkt_id to zero (invalid value) and check that
> >> it also overwritten.
> >>
> >> Fixes: fbfe568103b0 ("hash: use 32-bit elements rings to save
> >> memory")
> >> Cc: stable@dpdk.org
> >>
> >> Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
> >> ---
> >>  lib/librte_hash/rte_cuckoo_hash.c | 5 +++--
> >>  1 file changed, 3 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/lib/librte_hash/rte_cuckoo_hash.c
> >> b/lib/librte_hash/rte_cuckoo_hash.c
> >> index 38767a8a1..90cb99b0e 100644
> >> --- a/lib/librte_hash/rte_cuckoo_hash.c
> >> +++ b/lib/librte_hash/rte_cuckoo_hash.c
> >> @@ -940,6 +940,6 @@ __rte_hash_add_key_with_hash(const struct
> >> rte_hash *h, const void *key,
> >>  	struct rte_hash_bucket *prim_bkt, *sec_bkt, *cur_bkt;
> >>  	struct rte_hash_key *new_k, *keys = h->key_store;
> >> +	uint32_t ext_bkt_id = 0;
> >>  	uint32_t slot_id;
> >> -	uint32_t ext_bkt_id;
> >>  	int ret;
> >>  	unsigned n_slots;
> >> @@ -1096,5 +1096,6 @@ __rte_hash_add_key_with_hash(const struct
> >> rte_hash *h, const void *key,
> >>  	 */
> >>  	if (rte_ring_sc_dequeue_elem(h->free_ext_bkts, &ext_bkt_id,
> >> -						sizeof(uint32_t)) != 0) {
> >> +						sizeof(uint32_t)) != 0 ||
> >> +					ext_bkt_id == 0) {
> > [Wang, Yipeng]
> > If convenient, it would be better to make the two lines aligned with same
> indent...
> >
> 
> Hi Yipeng, I had checked the coding style [1] about this and I think
> it's correct as 'sizeof..' is a wrap from the first condition so gets a
> second tab to indicate that, whereas 'ext_bkt_id..' is the second
> condition with no wrap. Fine to change it, if I interpret incorrectly.
> 
> [1] third bullet,
> http://doc.dpdk.org/guides/contributing/coding_style.html#general
[Wang, Yipeng] I see your point now. Thanks for explaining and I think it makes sense to distinguish these two.
I guess it just came from my own aesthetic preference.
and I don’t have the best coding style : )

> 
> >>  		ret = -ENOSPC;
> >>  		goto failure;
> >> --
> >> 2.21.3
> > [Wang, Yipeng]
> > Thanks for the fix. I think It is also better code in general.
> >
> > Acked-by: Yipeng Wang <yipeng1.wang@intel.com>
> >

Re: [dpdk-dev] [PATCH] hash: fix gcc 10 maybe-uninitialized warning

[David Marchand]

On Fri, May 15, 2020 at 4:28 PM Kevin Traynor <ktraynor@redhat.com> wrote:
>
> gcc 10.1.1 reports a warning for the ext_bkt_id variable:
>
> ../lib/librte_hash/rte_cuckoo_hash.c:
> In function ‘__rte_hash_add_key_with_hash’:
> ../lib/librte_hash/rte_cuckoo_hash.c:1104:29:
> warning: ‘ext_bkt_id’ may be used uninitialized in this function
> [-Wmaybe-uninitialized]
>  1104 |  (h->buckets_ext[ext_bkt_id - 1]).sig_current[0] = short_sig;
>       |                  ~~~~~~~~~~~^~~
>
> The return value of rte_ring_sc_dequeue_elem() is already checked,
> but also initialize ext_bkt_id to zero (invalid value) and check
> that it also overwritten.
>
> Fixes: fbfe568103b0 ("hash: use 32-bit elements rings to save memory")
> Cc: stable@dpdk.org
>
> Signed-off-by: Kevin Traynor <ktraynor@redhat.com>

Acked-by: Yipeng Wang <yipeng1.wang@intel.com>


Applied, thanks.

-- 
David Marchand