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* [dpdk-dev] [PATCH] mbuf: fix reset on mbuf free
@ 2020-11-04 17:00 Olivier Matz
  2020-11-05  0:15 ` Ananyev, Konstantin
                   ` (4 more replies)
  0 siblings, 5 replies; 74+ messages in thread
From: Olivier Matz @ 2020-11-04 17:00 UTC (permalink / raw)
  To: dev; +Cc: konstantin.ananyev, stable

m->nb_seg must be reset on mbuf free whatever the value of m->next,
because it can happen that m->nb_seg is != 1. For instance in this
case:

  m1 = rte_pktmbuf_alloc(mp);
  rte_pktmbuf_append(m1, 500);
  m2 = rte_pktmbuf_alloc(mp);
  rte_pktmbuf_append(m2, 500);
  rte_pktmbuf_chain(m1, m2);
  m0 = rte_pktmbuf_alloc(mp);
  rte_pktmbuf_append(m0, 500);
  rte_pktmbuf_chain(m0, m1);

As rte_pktmbuf_chain() does not reset nb_seg in the initial m1
segment (this is not required), after this code the mbuf chain
have 3 segments:
  - m0: next=m1, nb_seg=3
  - m1: next=m2, nb_seg=2
  - m2: next=NULL, nb_seg=1

Freeing this mbuf chain will not restore nb_seg=1 in the second
segment. This is expected that mbufs stored in pool have their
nb_seg field set to 1.

Fixes: 8f094a9ac5d7 ("mbuf: set mbuf fields while in pool")
Cc: stable@dpdk.org

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 lib/librte_mbuf/rte_mbuf.c |  6 ++----
 lib/librte_mbuf/rte_mbuf.h | 12 ++++--------
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
index 8a456e5e64..e632071c23 100644
--- a/lib/librte_mbuf/rte_mbuf.c
+++ b/lib/librte_mbuf/rte_mbuf.c
@@ -129,10 +129,8 @@ rte_pktmbuf_free_pinned_extmem(void *addr, void *opaque)
 
 	rte_mbuf_ext_refcnt_set(m->shinfo, 1);
 	m->ol_flags = EXT_ATTACHED_MBUF;
-	if (m->next != NULL) {
-		m->next = NULL;
-		m->nb_segs = 1;
-	}
+	m->next = NULL;
+	m->nb_segs = 1;
 	rte_mbuf_raw_free(m);
 }
 
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index a1414ed7cd..ef5800c8ef 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -1329,10 +1329,8 @@ rte_pktmbuf_prefree_seg(struct rte_mbuf *m)
 				return NULL;
 		}
 
-		if (m->next != NULL) {
-			m->next = NULL;
-			m->nb_segs = 1;
-		}
+		m->next = NULL;
+		m->nb_segs = 1;
 
 		return m;
 
@@ -1346,10 +1344,8 @@ rte_pktmbuf_prefree_seg(struct rte_mbuf *m)
 				return NULL;
 		}
 
-		if (m->next != NULL) {
-			m->next = NULL;
-			m->nb_segs = 1;
-		}
+		m->next = NULL;
+		m->nb_segs = 1;
 		rte_mbuf_refcnt_set(m, 1);
 
 		return m;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 74+ messages in thread

end of thread, other threads:[~2022-07-28 14:07 UTC | newest]

Thread overview: 74+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-11-04 17:00 [dpdk-dev] [PATCH] mbuf: fix reset on mbuf free Olivier Matz
2020-11-05  0:15 ` Ananyev, Konstantin
2020-11-05  7:46   ` Olivier Matz
2020-11-05  8:26     ` Andrew Rybchenko
2020-11-05  9:10       ` Olivier Matz
2020-11-05 11:34         ` Ananyev, Konstantin
2020-11-05 12:31           ` Olivier Matz
2020-11-05 13:14             ` Ananyev, Konstantin
2020-11-05 13:24               ` Olivier Matz
2020-11-05 13:55                 ` Ananyev, Konstantin
2020-11-05 16:30                   ` Morten Brørup
2020-11-05 23:55                     ` Ananyev, Konstantin
2020-11-06  7:52                       ` Morten Brørup
2020-11-06  8:20                         ` Olivier Matz
2020-11-06  8:50                           ` Morten Brørup
2020-11-06 10:04                             ` Olivier Matz
2020-11-06 10:07                               ` Morten Brørup
2020-11-06 11:53                                 ` Ananyev, Konstantin
2020-11-06 12:23                                   ` Morten Brørup
2020-11-08 14:16                                     ` Andrew Rybchenko
2020-11-08 14:19                                       ` Ananyev, Konstantin
2020-11-10 16:26                                         ` Olivier Matz
2020-11-05  8:33     ` Morten Brørup
2020-11-05  9:03       ` Olivier Matz
2020-11-05  9:09     ` Andrew Rybchenko
2020-11-08  7:25 ` Ali Alnubani
2020-12-18 12:52 ` [dpdk-dev] [PATCH v2] " Olivier Matz
2020-12-18 13:18   ` Morten Brørup
2020-12-18 23:33     ` Ajit Khaparde
2021-01-06 13:33 ` [dpdk-dev] [PATCH v3] " Olivier Matz
2021-01-10  9:28   ` Ali Alnubani
2021-01-11 13:14   ` Ananyev, Konstantin
2021-01-13 13:27 ` [dpdk-dev] [PATCH v4] " Olivier Matz
2021-01-15 13:59   ` [dpdk-dev] [dpdk-stable] " David Marchand
2021-01-15 18:39     ` Ali Alnubani
2021-01-18 17:52       ` Ali Alnubani
2021-01-19  8:32         ` Olivier Matz
2021-01-19  8:53           ` Morten Brørup
2021-01-19 12:00             ` Ferruh Yigit
2021-01-19 12:27               ` Morten Brørup
2021-01-19 14:03                 ` Ferruh Yigit
2021-01-19 14:21                   ` Morten Brørup
2021-01-21  9:15                     ` Ferruh Yigit
2021-01-19 14:04           ` Slava Ovsiienko
2021-07-24  8:47             ` Thomas Monjalon
2021-07-30 12:36               ` Olivier Matz
2021-07-30 14:35                 ` Morten Brørup
2021-07-30 14:54                   ` Thomas Monjalon
2021-07-30 15:14                     ` Olivier Matz
2021-07-30 15:23                       ` Morten Brørup
2021-08-04 13:29                       ` [dpdk-dev] [PATCH] doc: add known issue with mbuf segment Thomas Monjalon
2021-08-04 14:25                         ` Ajit Khaparde
2021-08-05  6:08                         ` Morten Brørup
2021-08-06 14:21                           ` Thomas Monjalon
2021-08-06 14:24                             ` Morten Brørup
2021-09-28  8:28                     ` [dpdk-dev] [dpdk-stable] [PATCH v4] mbuf: fix reset on mbuf free Thomas Monjalon
2021-09-28  9:00                       ` Slava Ovsiienko
2021-09-28  9:25                         ` Ananyev, Konstantin
2021-09-28  9:39                         ` Morten Brørup
2021-09-29  8:03                           ` Ali Alnubani
2021-09-29 21:39                             ` Olivier Matz
2021-09-30 13:29                               ` Ali Alnubani
2021-10-21  8:26                                 ` Thomas Monjalon
2021-01-21  9:19       ` Ferruh Yigit
2021-01-21  9:29         ` Morten Brørup
2021-01-21 16:35           ` [dpdk-dev] [dpdklab] " Lincoln Lavoie
2021-01-23  8:57             ` Morten Brørup
2021-01-25 17:00               ` Brandon Lo
2021-01-25 18:42             ` Ferruh Yigit
2021-06-15 13:56   ` [dpdk-dev] " Morten Brørup
2021-09-29 21:37   ` [dpdk-dev] [PATCH v5] " Olivier Matz
2021-09-30 13:27     ` Ali Alnubani
2021-10-21  9:18     ` David Marchand
2022-07-28 14:06       ` CI performance test results might be misleading Morten Brørup

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