CVE-2026-45880 Linux CVE debrief

Who should care

Linux system administrators managing servers with PCI P2PDMA-capable devices; kernel maintainers; organizations running workloads that utilize peer-to-peer DMA between PCI devices

Technical summary

The vulnerability exists in drivers/pci/p2pdma.c in the p2pmem_alloc_mmap() function. After successfully allocating memory from the gen_pool via gen_pool_alloc_owner(), a per-CPU reference is acquired via percpu_ref_get(). If the subsequent vm_insert_page() call fails to map the page into user space, the error handling path returns without calling percpu_ref_put() to release the reference. This leaves the pgmap reference count elevated. When the PCI device is later removed, memunmap_pages() waits indefinitely for the reference count to reach zero, causing a hang. The fix adds the missing percpu_ref_put() call in the error path before returning.

Defensive priority

medium

Recommended defensive actions

• Apply kernel updates containing the referenced stable commits when available from your Linux distribution
• Monitor NVD for CVSS scoring once analysis is complete
• Review systems utilizing PCI P2PDMA functionality for stability issues during device hotplug operations
• Consider proactive patching for systems with high-availability requirements for PCI device management

Evidence notes

Vulnerability description confirms missing percpu_ref_put() in error path when vm_insert_page() fails. Kernel commit references indicate fixes applied to stable branches. No CVSS score assigned yet by NVD (status: Awaiting Analysis).

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.