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

octeontx2-af: Workaround SQM/PSE stalls by disabling sticky

NIX SQ manager sticky mode is known to cause stalls when multiple SQs
share an SMQ and transmit concurrently. Additionally, PSE may deadlock
on transitions between sticky and non-sticky transmissions. There is
also a credit drop issue observed when certain condition clocks are
gated.

work around these hardware errata by:
- Disabling SQM sticky operation:
- Clear TM6 (bit 15)
- Clear TM11 (bit 14)
- Disabling sticky → non-sticky transition path that can deadlock PSE:
- Clear TM5 (bit 23)
- Preventing credit drops by keeping the control-flow clock enabled:
- Set TM9 (bit 21)

These changes are applied via NIX_AF_SQM_DBG_CTL_STATUS. With this
configuration the SQM/PSE maintain forward progress under load without
credit loss, at the cost of disabling sticky optimizations.
Published: 2026-05-08
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The kernel bug involves the NIX SQ manager sticky mode. With multiple SQs sharing an SMQ and transmitting at the same time, sticky mode can cause stalls, while transitions between sticky and non‑sticky transmissions may deadlock PSE. Additionally, a credit drop can happen when certain condition clocks are gated. These hardware errata result in performance degradation, potential service disruption, or complete deadlock and are mitigated by disabling sticky optimizations.

Affected Systems

The issue affects Linux kernel deployments that run on OcteonTX2 processors using the NIX interface. All kernel versions that support the affected hardware are potentially impacted. The affected component is the NIX AF SQM debug control/status register accessed through the kernel.

Risk and Exploitability

EPSS data is not available, so the probability of exploitation cannot be quantified. The flaw is not exposed via a network or software interface that would allow a remote attacker to trigger it; this inference is based on the description, which indicates a hardware errata that manifests under specific in‑kernel conditions. A workload that stresses the hardware could trigger the stalls, but no publicly known exploit exists, and the issue does not appear in the CISA KEV catalog. The CVSS score of 5.5 indicates medium severity. Therefore, the overall risk is limited to availability and performance concerns rather than a security compromise.

Generated by OpenCVE AI on May 9, 2026 at 01:47 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the kernel change that clears bits TM6 (bit 15) and TM11 (bit 14) in NIX_AF_SQM_DBG_CTL_STATUS to disable SQM sticky operation.
  • Clear bit 23 (TM5) in NIX_AF_SQM_DBG_CTL_STATUS to prevent deadlocking between sticky and non‑sticky PSE transmissions.
  • Set bit 21 (TM9) in NIX_AF_SQM_DBG_CTL_STATUS to keep the control‑flow clock enabled and avoid credit drops.
  • Deploy the patched kernel on all OcteonTX2‑based hosts, ensuring the NIX_AF_SQM_DBG_CTL_STATUS register is updated accordingly.

Generated by OpenCVE AI on May 9, 2026 at 01:47 UTC.

Tracking

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Advisories

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History

Sat, 09 May 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-833
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Fri, 08 May 2026 16:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-361

Fri, 08 May 2026 13:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: octeontx2-af: Workaround SQM/PSE stalls by disabling sticky NIX SQ manager sticky mode is known to cause stalls when multiple SQs share an SMQ and transmit concurrently. Additionally, PSE may deadlock on transitions between sticky and non-sticky transmissions. There is also a credit drop issue observed when certain condition clocks are gated. work around these hardware errata by: - Disabling SQM sticky operation: - Clear TM6 (bit 15) - Clear TM11 (bit 14) - Disabling sticky → non-sticky transition path that can deadlock PSE: - Clear TM5 (bit 23) - Preventing credit drops by keeping the control-flow clock enabled: - Set TM9 (bit 21) These changes are applied via NIX_AF_SQM_DBG_CTL_STATUS. With this configuration the SQM/PSE maintain forward progress under load without credit loss, at the cost of disabling sticky optimizations.
Title octeontx2-af: Workaround SQM/PSE stalls by disabling sticky
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-09T04:10:08.683Z

Reserved: 2026-05-01T14:12:55.999Z

Link: CVE-2026-43296

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-08T14:16:36.727

Modified: 2026-05-08T14:16:36.727

Link: CVE-2026-43296

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-05-08T00:00:00Z

Links: CVE-2026-43296 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-09T02:00:19Z

Weaknesses