CVE-2024-26684

What it actually does

Unhandled Data Path Parity Errors for DMA channels in XGMAC core cause repeated interrupts that are never cleared, resulting in interrupt storms and potential denial of service.

Why it matters to the business

Affected Linux systems may experience network instability, excessive CPU usage from interrupt handling, or complete unresponsiveness on devices using stmmac/xgmac Ethernet controllers.

How an attack unfolds

An attacker or faulty hardware triggers Data Path Parity safety errors on DMA channels; the kernel fails to check or clear the DMA_DPP_Interrupt_Status register, flooding the system with unhandled interrupts.

How to fix it

Update the Linux kernel to the fixed commit e9837c83befb5b852fa76425dde98a87b737df00 or later stable release containing the fix for DMA_DPP_Interrupt_Status handling.

How to confirm the fix worked

Confirm the patch is applied by verifying presence of the DMA_DPP_Interrupt_Status register check and clear logic in the stmmac xgmac driver; test by inducing a parity error and observing single interrupt handling instead of a storm.

Typical attack path

1. Trigger parity or safety error condition on DMA channel
2. Kernel logs the error but leaves DMA_DPP_Interrupt_Status uncleared
3. Interrupt storm consumes CPU and prevents normal operation

How to detect it

Review kernel logs for repeated stmmac safety error messages without corresponding DMA_DPP_Interrupt_Status clears; correlate with high interrupt counts on Ethernet interfaces.

What your security team should do

• Prioritize kernel upgrade on all systems using stmmac/xgmac controllers
• Monitor for unusual interrupt rates on network interfaces
• Apply the fix before the next scheduled maintenance window given the age of the vulnerability