Description
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5e: Fix publication race for priv->channel_stats[]

mlx5e_channel_stats_alloc() publishes a new entry to
priv->channel_stats[] and then increments priv->stats_nch as a
publication token, but neither store carries any memory barrier:

priv->channel_stats[ix] = kvzalloc_node(...);
if (!priv->channel_stats[ix])
return -ENOMEM;
priv->stats_nch++;

Concurrent readers compute the loop bound from priv->stats_nch and
then dereference priv->channel_stats[i] using plain accesses, e.g.

for (i = 0; i < priv->stats_nch; i++) {
struct mlx5e_channel_stats *cs = priv->channel_stats[i];
... cs->rq.packets ...
}

On weakly-ordered architectures (ARM, PowerPC, RISC-V) the writes to
channel_stats[ix] and stats_nch may become visible to other CPUs out
of program order. A reader can observe stats_nch == N while still
seeing channel_stats[N-1] == NULL, leading to a NULL pointer
dereference in the channel_stats loop.

This has been observed in production on BlueField-3 DPUs (arm64),
where ovs-vswitchd queries netdev statistics over netlink during NIC
bringup, racing mlx5e_open_channel() -> mlx5e_channel_stats_alloc()
on another CPU:

Unable to handle kernel NULL pointer dereference at virtual address 0x840
Hardware name: BlueField-3 DPU
pc : mlx5e_fold_sw_stats64+0x30/0x180 [mlx5_core]
Call trace:
mlx5e_fold_sw_stats64+0x30/0x180 [mlx5_core]
dev_get_stats+0x50/0xc0
ovs_vport_get_stats+0x38/0xac [openvswitch]
ovs_vport_cmd_fill_info+0x194/0x290 [openvswitch]
ovs_vport_cmd_get+0xbc/0x10c [openvswitch]
genl_family_rcv_msg_doit+0xd0/0x160
genl_rcv_msg+0xec/0x1f0
netlink_rcv_skb+0x64/0x130
genl_rcv+0x40/0x60
netlink_unicast+0x2fc/0x370
netlink_sendmsg+0x1dc/0x454
...
__arm64_sys_sendmsg+0x2c/0x40

Add mlx5e_stats_nch_write() and mlx5e_stats_nch_read() helpers in en.h
that wrap the smp_store_release()/smp_load_acquire() pair on stats_nch.
The release/acquire pair establishes the contract:

stats_nch == N => channel_stats[0..N-1] are visible and non-NULL.

Publish the stats_nch increment via mlx5e_stats_nch_write() in the
writer (mlx5e_channel_stats_alloc()), and read stats_nch via
mlx5e_stats_nch_read() in all readers: mlx5e RX/TX queue stats,
mlx5e_get_base_stats(), ethtool channels stats, IPoIB stats, the
sw_stats fold and the HV VHCA stats agent.
Published: 2026-08-15
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Sat, 15 Aug 2026 06:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix publication race for priv->channel_stats[] mlx5e_channel_stats_alloc() publishes a new entry to priv->channel_stats[] and then increments priv->stats_nch as a publication token, but neither store carries any memory barrier: priv->channel_stats[ix] = kvzalloc_node(...); if (!priv->channel_stats[ix]) return -ENOMEM; priv->stats_nch++; Concurrent readers compute the loop bound from priv->stats_nch and then dereference priv->channel_stats[i] using plain accesses, e.g. for (i = 0; i < priv->stats_nch; i++) { struct mlx5e_channel_stats *cs = priv->channel_stats[i]; ... cs->rq.packets ... } On weakly-ordered architectures (ARM, PowerPC, RISC-V) the writes to channel_stats[ix] and stats_nch may become visible to other CPUs out of program order. A reader can observe stats_nch == N while still seeing channel_stats[N-1] == NULL, leading to a NULL pointer dereference in the channel_stats loop. This has been observed in production on BlueField-3 DPUs (arm64), where ovs-vswitchd queries netdev statistics over netlink during NIC bringup, racing mlx5e_open_channel() -> mlx5e_channel_stats_alloc() on another CPU: Unable to handle kernel NULL pointer dereference at virtual address 0x840 Hardware name: BlueField-3 DPU pc : mlx5e_fold_sw_stats64+0x30/0x180 [mlx5_core] Call trace: mlx5e_fold_sw_stats64+0x30/0x180 [mlx5_core] dev_get_stats+0x50/0xc0 ovs_vport_get_stats+0x38/0xac [openvswitch] ovs_vport_cmd_fill_info+0x194/0x290 [openvswitch] ovs_vport_cmd_get+0xbc/0x10c [openvswitch] genl_family_rcv_msg_doit+0xd0/0x160 genl_rcv_msg+0xec/0x1f0 netlink_rcv_skb+0x64/0x130 genl_rcv+0x40/0x60 netlink_unicast+0x2fc/0x370 netlink_sendmsg+0x1dc/0x454 ... __arm64_sys_sendmsg+0x2c/0x40 Add mlx5e_stats_nch_write() and mlx5e_stats_nch_read() helpers in en.h that wrap the smp_store_release()/smp_load_acquire() pair on stats_nch. The release/acquire pair establishes the contract: stats_nch == N => channel_stats[0..N-1] are visible and non-NULL. Publish the stats_nch increment via mlx5e_stats_nch_write() in the writer (mlx5e_channel_stats_alloc()), and read stats_nch via mlx5e_stats_nch_read() in all readers: mlx5e RX/TX queue stats, mlx5e_get_base_stats(), ethtool channels stats, IPoIB stats, the sw_stats fold and the HV VHCA stats agent.
Title net/mlx5e: Fix publication race for priv->channel_stats[]
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-15T05:55:47.764Z

Reserved: 2026-08-09T03:40:39.920Z

Link: CVE-2026-72341

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-15T06:22:07.403

Modified: 2026-08-15T06:22:07.403

Link: CVE-2026-72341

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.