Executive brief
A technical issue was identified in the Linux kernel's handling of Peer-to-Peer Direct Memory Access (P2PDMA). When specific debugging features are enabled, the system may trigger a kernel warning or crash due to an incorrect internal check during memory allocation. This primarily affects system stability and diagnostic logging rather than direct data security.
Technical details
The vulnerability stems from an incorrect assertion condition in the p2pmem_alloc_mmap() function within drivers/pci/p2pdma.c. A previous commit (b7e282378773) changed the initial page reference count for P2PDMA pages from one to zero, but the code continued to use VM_WARN_ON_ONCE_PAGE(!page_ref_count(page)) to verify the page state. This caused a kernel warning when CONFIG_DEBUG_VM was enabled because the check expected a non-zero count. The fix updates the assertion to correctly reflect the expected zero reference count at that stage of allocation. This is a local issue affecting system stability and kernel log integrity.
Affected products
- Linux Linux kernel All versions prior to the fix in 2026-02-26
Timeline
- 2025-12-20: other: Patch authored
- 2026-01-08: patched: Mainline fix committed
- 2026-06-03: disclosed: CVE published