CVE-2025-71078

/// Technical description

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

powerpc/64s/slb: Fix SLB multihit issue during SLB preload

On systems using the hash MMU, there is a software SLB preload cache that

mirrors the entries loaded into the hardware SLB buffer. This preload

cache is subject to periodic eviction — typically after every 256 context

switches — to remove old entry.

To optimize performance, the kernel skips switch_mmu_context() in

switch_mm_irqs_off() when the prev and next mm_struct are the same.

However, on hash MMU systems, this can lead to inconsistencies between

the hardware SLB and the software preload cache.

If an SLB entry for a process is evicted from the software cache on one

CPU, and the same process later runs on another CPU without executing

switch_mmu_context(), the hardware SLB may retain stale entries. If the

kernel then attempts to reload that entry, it can trigger an SLB

multi-hit error.

The following timeline shows how stale SLB entries are created and c

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References