Bug 2516625 (CVE-2026-72409) - CVE-2026-72409 kernel: net: mvneta: re-enable percpu interrupt on resume
Summary: CVE-2026-72409 kernel: net: mvneta: re-enable percpu interrupt on resume
Keywords:
Status: NEW
Alias: CVE-2026-72409
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-15 06:22 UTC by OSIDB Bzimport
Modified: 2026-08-19 15:55 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-08-15 06:22:36 UTC
In the Linux kernel, the following vulnerability has been resolved:

net: mvneta: re-enable percpu interrupt on resume

On Marvell MPIC platforms (Armada 370/XP/38x), mvneta uses a percpu
IRQ disable/enable scheme for NAPI: the ISR (mvneta_percpu_isr) calls
disable_percpu_irq() to mask the MPIC per-CPU interrupt and schedules
NAPI poll, which calls enable_percpu_irq() on completion to unmask.

If suspend occurs while NAPI poll is pending (between
disable_percpu_irq in the ISR and enable_percpu_irq in poll
completion), the interrupt is never re-enabled:

  1. mvneta_percpu_isr: disable_percpu_irq() + napi_schedule()
     => MPIC masked, percpu_enabled cpumask bit cleared
  2. NAPI poll does not complete before suspend proceeds
     (on PREEMPT_RT this is highly likely since softirqs run in
     ksoftirqd which gets frozen; on non-RT it can happen when
     softirq processing is deferred to ksoftirqd)
  3. mvneta_stop_dev => napi_disable(): cancels the pending poll
     without executing the completion path
  4. suspend_device_irqs => IRQCHIP_MASK_ON_SUSPEND: masks MPIC
     (already masked, but records IRQS_SUSPENDED)
  5. Resume: mpic_resume checks irq_percpu_is_enabled() => false
     (bit was cleared in step 1) => skips unmask
  6. mvneta_start_dev only restores device-level INTR_NEW_MASK,
     does not touch the MPIC per-CPU mask

Result: MPIC per-CPU interrupt stays masked permanently. The NIC
generates interrupts (INTR_NEW_CAUSE != 0) but the CPU never
receives them, causing complete loss of network connectivity.

Fix by calling on_each_cpu(mvneta_percpu_enable) in the resume path
to unconditionally unmask the MPIC per-CPU interrupt regardless of
pre-suspend state.


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