From: Robin Jarry <rjarry@redhat.com>
To: dev@dpdk.org
Subject: [PATCH dpdk v2] mbuf: fix strict aliasing error in allocator
Date: Wed, 25 Sep 2024 11:40:54 -0400 [thread overview]
Message-ID: <20240925154053.80861-2-rjarry@redhat.com> (raw)
In-Reply-To: <20240925140021.46320-2-rjarry@redhat.com>
When building an application with -fstrict-aliasing -Wstrict-aliasing=2,
we get errors triggered by rte_mbuf_raw_alloc() which is called inline
from rte_pktmbuf_alloc().
../dpdk/lib/mbuf/rte_mbuf.h: In function ‘rte_mbuf_raw_alloc’:
../dpdk/lib/mbuf/rte_mbuf.h:600:42: error: dereferencing type-punned
pointer might break strict-aliasing rules [-Werror=strict-aliasing]
600 | if (rte_mempool_get(mp, (void **)&m) < 0)
| ^~
Avoid incorrect casting by using an inline union variable.
Signed-off-by: Robin Jarry <rjarry@redhat.com>
---
Notes:
v2: use inline union to fix -Wincompatible-pointer-types
lib/mbuf/rte_mbuf.h | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/lib/mbuf/rte_mbuf.h b/lib/mbuf/rte_mbuf.h
index babe16c72ccb..0d2e0e64b3ce 100644
--- a/lib/mbuf/rte_mbuf.h
+++ b/lib/mbuf/rte_mbuf.h
@@ -595,12 +595,15 @@ __rte_mbuf_raw_sanity_check(__rte_unused const struct rte_mbuf *m)
*/
static inline struct rte_mbuf *rte_mbuf_raw_alloc(struct rte_mempool *mp)
{
- struct rte_mbuf *m;
+ union {
+ void *ptr;
+ struct rte_mbuf *m;
+ } ret;
- if (rte_mempool_get(mp, (void **)&m) < 0)
+ if (rte_mempool_get(mp, &ret.ptr) < 0)
return NULL;
- __rte_mbuf_raw_sanity_check(m);
- return m;
+ __rte_mbuf_raw_sanity_check(ret.m);
+ return ret.m;
}
/**
--
2.46.1
next prev parent reply other threads:[~2024-09-25 15:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-25 14:00 [PATCH dpdk] " Robin Jarry
2024-09-25 15:21 ` Morten Brørup
2024-09-25 15:23 ` Stephen Hemminger
2024-09-25 15:24 ` Robin Jarry
2024-09-25 15:40 ` Robin Jarry [this message]
2024-09-25 15:47 ` [PATCH dpdk v2] " Stephen Hemminger
2024-10-17 19:44 ` Thomas Monjalon
2024-10-17 14:17 ` Ali Alnubani
2024-09-26 16:38 ` [PATCH dpdk] " Patrick Robb
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