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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72341
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:22:07 UTC
Updated2026-08-17 06:18:37 UTC
DescriptionIn 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.

Risk And Classification

EPSS: 0.002070000 probability, percentile 0.110500000 (date 2026-08-17)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected fa691d0c9c0812b9045f3a9420862e47b3b92518 5c7e3755abf663f033de24f917b77685e9543045 git Not specified
CNA Linux Linux affected fa691d0c9c0812b9045f3a9420862e47b3b92518 815515ec68f527ca755cb1e2c1ff9148f6b3ea56 git Not specified
CNA Linux Linux affected fa691d0c9c0812b9045f3a9420862e47b3b92518 5a799714e8ca0bce9ea40694f49914cf1adbbaa9 git Not specified
CNA Linux Linux affected 5.17 Not specified
CNA Linux Linux unaffected 5.17 semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/815515ec68f527ca755cb1e2c1ff9148f6b3ea56 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/5c7e3755abf663f033de24f917b77685e9543045 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/5a799714e8ca0bce9ea40694f49914cf1adbbaa9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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