---
id: CVE-2026-43466
title: 'net/mlx5e: Fix DMA FIFO desync on error CQE SQ recovery'
summary: |-
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Fix DMA FIFO desync on error CQE SQ recovery
In case of a TX error CQE, a recovery flow is triggered,
mlx5e_reset_txqsq_cc_pc() resets dma_fifo_cc to 0 but …
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
- >-
Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 <
821f85d619f7f22cda7b9d7de89cf5eeb1d11544
- >-
Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 <
6eb68ecc5acc3b319986566c595990b8a7265b23
- >-
Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 <
6f41f7812bfa7f991b732a4b45c5c52fc4be3b4e
- >-
Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 <
383b37c04a4827ba60b2bafc1a6cdfd995aed58f
- >-
Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 <
9c5ee9b981ee050b73fdf3f4a2464d6f1a8e10a8
- >-
Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 <
ce1b19dd0684eeb68a124c11085bd611260b36d9
- >-
Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 <
829efcccfa8f69db5dc8332961295587d218cee6
- >-
Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 <
1633111d69053512d099658d4a05fc736fab36b0
- Linux 4.17
ssvc:
exploitation: none
automatable: 'yes'
technicalImpact: partial
timestamp: '2026-10-16T15:17:38.531482Z'
published: '2026-05-08'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:20:42.642Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-43466'
references:
- url: 'https://git.kernel.org/stable/c/821f85d619f7f22cda7b9d7de89cf5eeb1d11544'
- url: 'https://git.kernel.org/stable/c/6eb68ecc5acc3b319986566c595990b8a7265b23'
- url: 'https://git.kernel.org/stable/c/6f41f7812bfa7f991b732a4b45c5c52fc4be3b4e'
- url: 'https://git.kernel.org/stable/c/383b37c04a4827ba60b2bafc1a6cdfd995aed58f'
- url: 'https://git.kernel.org/stable/c/9c5ee9b981ee050b73fdf3f4a2464d6f1a8e10a8'
- url: 'https://git.kernel.org/stable/c/ce1b19dd0684eeb68a124c11085bd611260b36d9'
- url: 'https://git.kernel.org/stable/c/829efcccfa8f69db5dc8332961295587d218cee6'
- url: 'https://git.kernel.org/stable/c/1633111d69053512d099658d4a05fc736fab36b0'
tags:
- cve.org
epss: 0.00606
epssPercentile: 0.47898
ingestedAt: '2026-10-16T17:24:46.697Z'
---
## Overview
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Fix DMA FIFO desync on error CQE SQ recovery
In case of a TX error CQE, a recovery flow is triggered,
mlx5e_reset_txqsq_cc_pc() resets dma_fifo_cc to 0 but not dma_fifo_pc,
desyncing the DMA FIFO producer and consumer.
After recovery, the producer pushes new DMA entries at the old
dma_fifo_pc, while the consumer reads from position 0.
This causes us to unmap stale DMA addresses from before the recovery.
The DMA FIFO is a purely software construct with no HW counterpart.
At the point of reset, all WQEs have been flushed so dma_fifo_cc is
already equal to dma_fifo_pc. There is no need to reset either counter,
similar to how skb_fifo pc/cc are untouched.
Remove the 'dma_fifo_cc = 0' reset.
This fixes the following WARNING:
WARNING: CPU: 0 PID: 0 at drivers/iommu/dma-iommu.c:1240 iommu_dma_unmap_page+0x79/0x90
Modules linked in: mlx5_vdpa vringh vdpa bonding mlx5_ib mlx5_vfio_pci ipip mlx5_fwctl tunnel4 mlx5_core ib_ipoib geneve ip6_gre ip_gre gre nf_tables ip6_tunnel rdma_ucm ib_uverbs ib_umad vfio_pci vfio_pci_core act_mirred act_skbedit act_vlan vhost_net vhost tap ip6table_mangle ip6table_nat ip6table_filter ip6_tables iptable_mangle cls_matchall nfnetlink_cttimeout act_gact cls_flower sch_ingress vhost_iotlb iptable_raw tunnel6 vfio_iommu_type1 vfio openvswitch nsh rpcsec_gss_krb5 auth_rpcgss oid_registry xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat nf_nat xt_addrtype br_netfilter overlay zram zsmalloc rpcrdma ib_iser libiscsi scsi_transport_iscsi rdma_cm iw_cm ib_cm ib_core fuse [last unloaded: nf_tables]
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc5_for_upstream_min_debug_2024_12_30_21_33 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:iommu_dma_unmap_page+0x79/0x90
Code: 2b 4d 3b 21 72 26 4d 3b 61 08 73 20 49 89 d8 44 89 f9 5b 4c 89 f2 4c 89 e6 48 89 ef 5d 41 5c 41 5d 41 5e 41 5f e9 c7 ae 9e ff <0f> 0b 5b 5d 41 5c 41 5d 41 5e 41 5f c3 66 2e 0f 1f 84 00 00 00 00
Call Trace:
? __warn+0x7d/0x110
? iommu_dma_unmap_page+0x79/0x90
? report_bug+0x16d/0x180
? handle_bug+0x4f/0x90
? exc_invalid_op+0x14/0x70
? asm_exc_invalid_op+0x16/0x20
? iommu_dma_unmap_page+0x79/0x90
? iommu_dma_unmap_page+0x2e/0x90
dma_unmap_page_attrs+0x10d/0x1b0
mlx5e_tx_wi_dma_unmap+0xbe/0x120 [mlx5_core]
mlx5e_poll_tx_cq+0x16d/0x690 [mlx5_core]
mlx5e_napi_poll+0x8b/0xac0 [mlx5_core]
__napi_poll+0x24/0x190
net_rx_action+0x32a/0x3b0
? mlx5_eq_comp_int+0x7e/0x270 [mlx5_core]
? notifier_call_chain+0x35/0xa0
handle_softirqs+0xc9/0x270
irq_exit_rcu+0x71/0xd0
common_interrupt+0x7f/0xa0
asm_common_interrupt+0x22/0x40
## Affected
- `Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 < 821f85d619f7f22cda7b9d7de89cf5eeb1d11544`
- `Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 < 6eb68ecc5acc3b319986566c595990b8a7265b23`
- `Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 < 6f41f7812bfa7f991b732a4b45c5c52fc4be3b4e`
- `Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 < 383b37c04a4827ba60b2bafc1a6cdfd995aed58f`
- `Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 < 9c5ee9b981ee050b73fdf3f4a2464d6f1a8e10a8`
- `Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 < ce1b19dd0684eeb68a124c11085bd611260b36d9`
- `Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 < 829efcccfa8f69db5dc8332961295587d218cee6`
- `Linux >= db75373c91b0cfb6a68ad6ae88721e4e21ae6261 < 1633111d69053512d099658d4a05fc736fab36b0`
- `Linux 4.17`
## Remediation
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.