patch 'net/memif: fix descriptor Tx flags corruption' has been queued to stable release 24.11.5

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 24.11.5

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 03/21/26. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/bluca/dpdk-stable

This queued commit can be viewed at:
https://github.com/bluca/dpdk-stable/commit/d4246e342d2db7f8f59c256efd733fda364212b7

Thanks.

Luca Boccassi

---
>From d4246e342d2db7f8f59c256efd733fda364212b7 Mon Sep 17 00:00:00 2001
From: Sriram Yagnaraman <sriram.yagnaraman at ericsson.com>
Date: Tue, 3 Mar 2026 12:01:52 +0100
Subject: [PATCH] net/memif: fix descriptor Tx flags corruption

[ upstream commit f7a52200d4c2d12c0a35e643cb1d6fd45b21ccb7 ]

The memif Tx path was using |= to set descriptor flags, which could
leave stale flag bits from previous ring iterations. This caused
descriptor corruption when the ring wrapped around, leading to
malformed packet chains and RX failures.

Initialize d0->flags to 0 before setting MEMIF_DESC_FLAG_NEXT to
ensure clean descriptor state on each transmission.

Fixes: 43b815d88188 ("net/memif: support zero-copy slave")

Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman at ericsson.com>
---
 drivers/net/memif/rte_eth_memif.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/memif/rte_eth_memif.c b/drivers/net/memif/rte_eth_memif.c
index 3e6a3a41d9..a10d71f3ba 100644
--- a/drivers/net/memif/rte_eth_memif.c
+++ b/drivers/net/memif/rte_eth_memif.c
@@ -712,6 +712,7 @@ eth_memif_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 
 next_in_chain1:
 			d0 = &ring->desc[slot & mask];
+			d0->flags = 0;
 			cp_len = rte_pktmbuf_data_len(mbuf);
 
 			rte_memcpy((uint8_t *)memif_get_buffer(proc_private, d0),
@@ -724,7 +725,7 @@ next_in_chain1:
 
 			if (--nb_segs > 0) {
 				if (n_free) {
-					d0->flags |= MEMIF_DESC_FLAG_NEXT;
+					d0->flags = MEMIF_DESC_FLAG_NEXT;
 					mbuf = mbuf->next;
 					goto next_in_chain1;
 				} else {
@@ -745,6 +746,7 @@ free_mbufs:
 
 			saved_slot = slot;
 			d0 = &ring->desc[slot & mask];
+			d0->flags = 0;
 			dst_off = 0;
 			dst_len = (type == MEMIF_RING_C2S) ?
 				pmd->run.pkt_buffer_size : d0->length;
@@ -758,12 +760,12 @@ next_in_chain2:
 					if (n_free) {
 						slot++;
 						n_free--;
-						d0->flags |= MEMIF_DESC_FLAG_NEXT;
+						d0->flags = MEMIF_DESC_FLAG_NEXT;
 						d0 = &ring->desc[slot & mask];
+						d0->flags = 0;
 						dst_off = 0;
 						dst_len = (type == MEMIF_RING_C2S) ?
 						    pmd->run.pkt_buffer_size : d0->length;
-						d0->flags = 0;
 					} else {
 						slot = saved_slot;
 						goto no_free_slots;
-- 
2.47.3

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2026-03-19 22:00:49.315751714 +0000
+++ 0042-net-memif-fix-descriptor-Tx-flags-corruption.patch	2026-03-19 22:00:47.814359367 +0000
@@ -1 +1 @@
-From f7a52200d4c2d12c0a35e643cb1d6fd45b21ccb7 Mon Sep 17 00:00:00 2001
+From d4246e342d2db7f8f59c256efd733fda364212b7 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit f7a52200d4c2d12c0a35e643cb1d6fd45b21ccb7 ]
+
@@ -15 +16,0 @@
-Cc: stable at dpdk.org
@@ -23 +24 @@
-index 8d7060cd7c..effcee3721 100644
+index 3e6a3a41d9..a10d71f3ba 100644
@@ -26 +27 @@
-@@ -714,6 +714,7 @@ eth_memif_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
+@@ -712,6 +712,7 @@ eth_memif_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
@@ -34 +35 @@
-@@ -726,7 +727,7 @@ next_in_chain1:
+@@ -724,7 +725,7 @@ next_in_chain1:
@@ -43 +44 @@
-@@ -747,6 +748,7 @@ free_mbufs:
+@@ -745,6 +746,7 @@ free_mbufs:
@@ -51 +52 @@
-@@ -760,12 +762,12 @@ next_in_chain2:
+@@ -758,12 +760,12 @@ next_in_chain2: