---
id: CVE-2026-98920
title: 'netfs: Fix missing alloc tagging of direct mempool allocations'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfs: Fix missing alloc tagging of direct mempool allocations

  Commit 1d78d56c43ef ("netfs: Fix folio_queue ENOMEM in writeback by
  adding a mempool") added a mempool f…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 15ed8a9b7c63e9171f5139a6aaa1ffb61809861f <
    5c03da745171485fd181f17b69213464f6d05f3d
  - >-
    Linux >= 1d78d56c43ef3768183e8370e7367b162700e049 <
    37a2042748bc880df03ff8315db86ed82991fbb8
  - >-
    Linux >= 1d78d56c43ef3768183e8370e7367b162700e049 <
    b78b728e21c32ec4c330b299f657fb1eb02dffc2
  - Linux b343252d6f536203dd0660f676190dcbf6d2ecdc
  - Linux 3f6d7f8a5416d852648d15a05e895f1195ee8a85
  - Linux >= 6.12.114 < 6.13
  - Linux >= 7.1.8 < 7.2
  - Linux 7.2
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T12:05:25.919Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98920'
references:
  - url: 'https://git.kernel.org/stable/c/5c03da745171485fd181f17b69213464f6d05f3d'
  - url: 'https://git.kernel.org/stable/c/37a2042748bc880df03ff8315db86ed82991fbb8'
  - url: 'https://git.kernel.org/stable/c/b78b728e21c32ec4c330b299f657fb1eb02dffc2'
tags:
  - cve.org
ingestedAt: '2026-10-23T13:24:55.570Z'
---

## Overview

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

netfs: Fix missing alloc tagging of direct mempool allocations

Commit 1d78d56c43ef ("netfs: Fix folio_queue ENOMEM in writeback by
adding a mempool") added a mempool for the folio_queues and made the
request, subrequest and folio_queue allocations distinguish between
writeback and everything else.  Writeback is part of memory reclaim
and must not fail due to ENOMEM, so it allocates under GFP_NOFS
through mempool_alloc(), which may dip into the pool's reserve and,
if that runs empty, wait for elements to be returned.  The
GFP_KERNEL paths, which can return -ENOMEM to their callers, invoke
the pool's ->alloc() callback directly instead.

The direct call, however, skips the alloc_hooks() wrapper that the
mempool_alloc() macro provides.  The pool callbacks, mempool_alloc_slab()
and mempool_kmalloc(), call kmem_cache_alloc_noprof() and kmalloc_noprof()
and rely on current->alloc_tag having been set by the caller.  With
CONFIG_MEM_ALLOC_PROFILING_DEBUG=y this leads to

    current->alloc_tag not set
    WARNING: ./include/linux/alloc_tag.h:161 at __alloc_tagging_slab_alloc_hook
    alloc_tag was not set
    WARNING: ./include/linux/alloc_tag.h:166 at __alloc_tagging_slab_free_hook

at allocation and free time respectively, as reported when reading
files on a CIFS mount.  The allocations are also missing from
/proc/allocinfo.

Wrap the direct ->alloc() invocations in alloc_hooks() with a new
mempool_alloc_noreserve() helper in include/linux/mempool.h, next to
the other alloc_hooks()-wrapped macros such as mempool_alloc().  The
GFP_KERNEL paths keep their failable allocation semantics, they just
get tagged now.

## Affected

- `Linux >= 15ed8a9b7c63e9171f5139a6aaa1ffb61809861f < 5c03da745171485fd181f17b69213464f6d05f3d`
- `Linux >= 1d78d56c43ef3768183e8370e7367b162700e049 < 37a2042748bc880df03ff8315db86ed82991fbb8`
- `Linux >= 1d78d56c43ef3768183e8370e7367b162700e049 < b78b728e21c32ec4c330b299f657fb1eb02dffc2`
- `Linux b343252d6f536203dd0660f676190dcbf6d2ecdc`
- `Linux 3f6d7f8a5416d852648d15a05e895f1195ee8a85`
- `Linux >= 6.12.114 < 6.13`
- `Linux >= 7.1.8 < 7.2`
- `Linux 7.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.