CVE-2026-43296: octeontx2-af: Workaround SQM/PSE stalls by disabling sticky
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 NIXAFSQMDBGCTLSTATUS. With this configuration the SQM/PSE maintain forward progress under load without credit loss, at the cost of disabling sticky optimizations.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Apply the NIX_AF_SQM_DBG_CTL_STATUS workaround to clear TM11 (bit 14).
octeontx2-af (NIX_AF_SQM_DBG_CTL_STATUS) TM11 bit 14 = clear - Configuration
Apply the NIX_AF_SQM_DBG_CTL_STATUS workaround to clear TM5 (bit 23).
octeontx2-af (NIX_AF_SQM_DBG_CTL_STATUS) TM5 bit 23 = clear - Configuration
Apply the NIX_AF_SQM_DBG_CTL_STATUS workaround to clear TM6 (bit 15).
octeontx2-af (NIX_AF_SQM_DBG_CTL_STATUS) TM6 bit 15 = clear - Configuration
Configure NIX_AF_SQM_DBG_CTL_STATUS to disable SQM sticky operation (avoid the sticky → non-sticky transition path that can deadlock PSE), trading off sticky optimization for forward progress under load.
octeontx2-af (NIX_AF_SQM_DBG_CTL_STATUS) Disabling SQM sticky operation / sticky→non-sticky transition deadlock path = disable sticky optimizations - Configuration
Apply the NIX_AF_SQM_DBG_CTL_STATUS workaround to set TM9 (bit 21).
octeontx2-af (NIX_AF_SQM_DBG_CTL_STATUS) TM9 bit 21 = set - Compensating control
To maintain forward progress under load without credit loss, keep the control-flow clock enabled while applying the SQM/PSE sticky-disable workaround (at the cost of disabling sticky optimizations).
Event History
Frequently Asked Questions
What is the severity of CVE-2026-43296?
CVE-2026-43296 has a medium severity rating due to the potential for performance degradation in systems using the affected component.
How do I mitigate CVE-2026-43296?
To mitigate CVE-2026-43296, disable the sticky mode in the NIX SQ manager to prevent stalls when multiple SQs share an SMQ.
What systems are affected by CVE-2026-43296?
CVE-2026-43296 affects the Linux kernel with the octeontx2-af driver.
What type of vulnerability is CVE-2026-43296?
CVE-2026-43296 is categorized as a performance-related vulnerability.
Is there a patch available for CVE-2026-43296?
Yes, a patch for CVE-2026-43296 is available in the latest Linux kernel updates.