Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: mm/util: don't read __page_2 for order-1 folios in snapshot_page() snapshot_page() currently reads __page_2 after checking nr_pages > 1, but it should only do so when nr_pages > 2. If an order-1 folio is allocated at the end of a vmemmap section, __page_2 will not exist and reading it will cause a fault. During DLPAR memory remove on a 22 TB ppc64le LPAR, snapshot_page() oopsed on the page isolation path while reading an order-1 folio's __page_2 from an adjacent absent section (unmapped vmemmap). Fix this to avoid reading memmap that doesn't exist (e.g., a vmemmap hole).

Affected versions

Linux: 31a31da8a6187f1e5448ec73222e01d7d3fed4aa through before 9668ffe0e2a5e2399dce281620198a2e415871fc (git); 31a31da8a6187f1e5448ec73222e01d7d3fed4aa through before c649324571206a30949765320b91ccdb4c1722dc (git); 31a31da8a6187f1e5448ec73222e01d7d3fed4aa through before 7441d6348c70738e9ed307510db171c7a9b3f4bf (git); 4117738bd42c8ab58090729daf0f8472a936f662 (git); 6.12.111 through before 6.13 (semver); 6.15 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.