NFS: Charge unstable writes by request size, not folio size
Summary
| CVE | CVE-2026-72132 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-15 06:21:30 UTC |
| Updated | 2026-08-17 06:18:12 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: NFS: Charge unstable writes by request size, not folio size nfs_folio_mark_unstable() and nfs_folio_clear_commit() charge and uncharge NR_WRITEBACK/WB_WRITEBACK by folio_nr_pages(folio) once per *request* added to or removed from a commit list. This is correct only when a folio has a single associated request. When pg_test splits a folio into N sub-folio requests (e.g. pNFS flexfiles striping with a stripe unit smaller than the folio size, or plain wsize-limited splitting), each of the N requests independently charges the whole folio's page count, inflating the accounting by a factor of N per folio. With large folios and small stripe units this reaches multiple orders of magnitude: a 2 MiB folio split into 512 4 KiB requests can charge up to 512x its real size, pushing global dirty+writeback accounting past the system's dirty threshold and forcing every buffered writer on the host into the hard-throttle path, including unrelated in-kernel NFS server threads sharing the box. Charge each request only for the pages it actually covers. |
Risk And Classification
EPSS: 0.002000000 probability, percentile 0.101560000 (date 2026-08-17)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 0c493b5cf16e28d761b6e77c7c32aa0e7af70813 a442c258320b689f13d2205eaeeddf8b0e630288 git | Not specified |
| CNA | Linux | Linux | affected 0c493b5cf16e28d761b6e77c7c32aa0e7af70813 1f646e23372f3444dc5f0bcb5404a49d26756add git | Not specified |
| CNA | Linux | Linux | affected 0c493b5cf16e28d761b6e77c7c32aa0e7af70813 0ffc032294a29601b1019dba91aa1a930d90df17 git | Not specified |
| CNA | Linux | Linux | affected 0c493b5cf16e28d761b6e77c7c32aa0e7af70813 a192b6c149c6ea10cc88869accb78165eb454456 git | Not specified |
| CNA | Linux | Linux | affected 0c493b5cf16e28d761b6e77c7c32aa0e7af70813 27934d02cbeb8a957dd11c985a579e58d30c5270 git | Not specified |
| CNA | Linux | Linux | affected 6.3 | Not specified |
| CNA | Linux | Linux | unaffected 6.3 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.148 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.97 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.40 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.5 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/27934d02cbeb8a957dd11c985a579e58d30c5270 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/0ffc032294a29601b1019dba91aa1a930d90df17 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/a192b6c149c6ea10cc88869accb78165eb454456 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/a442c258320b689f13d2205eaeeddf8b0e630288 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/1f646e23372f3444dc5f0bcb5404a49d26756add | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.