Executive brief
The Linux kernel's network driver for Marvell MPIC platforms (used in many embedded systems and network appliances) has a flaw where network interrupts can become permanently disabled after system resume. If the system suspends while interrupt processing is in progress, the network interface stops receiving interrupts entirely, causing complete loss of network connectivity until the system is rebooted or manually recovered.
Technical details
This is a race condition in the mvneta driver's per-CPU interrupt handling scheme. The vulnerability occurs when system suspend happens between disable_percpu_irq() in the ISR and enable_percpu_irq() in the NAPI poll completion path. On resume, the mpic_resume function checks if the interrupt was previously enabled and skips re-enabling it if the flag indicates it was disabled—which it was, due to the incomplete interrupt handling sequence. The attack vector is local (requiring ability to trigger suspend/resume), and the impact is denial of service via permanent network outage. A fix is available that unconditionally unmasks MPIC per-CPU interrupts during resume regardless of pre-suspend state.
Affected products
- Linux Linux kernel Not specified in advisory
Timeline
- 2026-08-15: disclosed
- patched: Fix available via on_each_cpu(mvneta_percpu_enable) in resume path