From: "Wang, Yipeng1" <yipeng1.wang@intel.com>
To: Kevin Traynor <ktraynor@redhat.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"Gobriel, Sameh" <sameh.gobriel@intel.com>,
"Richardson, Bruce" <bruce.richardson@intel.com>
Cc: "honnappa.nagarahalli@arm.com" <honnappa.nagarahalli@arm.com>,
"Yigit, Ferruh" <ferruh.yigit@intel.com>,
"david.marchand@redhat.com" <david.marchand@redhat.com>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [PATCH] hash: fix gcc 10 maybe-uninitialized warning
Date: Fri, 15 May 2020 20:04:03 +0000 [thread overview]
Message-ID: <MW3PR11MB46843F11000D1F572A69A982C3BD0@MW3PR11MB4684.namprd11.prod.outlook.com> (raw)
In-Reply-To: <5dfbc47f-93eb-cc49-98eb-7c3375e08cae@redhat.com>
> -----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>
> >
next prev parent reply other threads:[~2020-05-15 20:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 14:28 Kevin Traynor
2020-05-15 19:06 ` Wang, Yipeng1
2020-05-15 19:17 ` Kevin Traynor
2020-05-15 20:04 ` Wang, Yipeng1 [this message]
2020-05-18 11:48 ` David Marchand
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