Vulnerability-Lookup

GHSA-C3HX-25RR-8X92

Vulnerability from github – Published: 2026-10-23 15:31 – Updated: 2026-10-23 15:31

Details

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.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98920"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-23T13:17:12Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix missing alloc tagging of direct mempool allocations\n\nCommit 1d78d56c43ef (\"netfs: Fix folio_queue ENOMEM in writeback by\nadding a mempool\") added a mempool for the folio_queues and made the\nrequest, subrequest and folio_queue allocations distinguish between\nwriteback and everything else.  Writeback is part of memory reclaim\nand must not fail due to ENOMEM, so it allocates under GFP_NOFS\nthrough mempool_alloc(), which may dip into the pool\u0027s reserve and,\nif that runs empty, wait for elements to be returned.  The\nGFP_KERNEL paths, which can return -ENOMEM to their callers, invoke\nthe pool\u0027s -\u003ealloc() callback directly instead.\n\nThe direct call, however, skips the alloc_hooks() wrapper that the\nmempool_alloc() macro provides.  The pool callbacks, mempool_alloc_slab()\nand mempool_kmalloc(), call kmem_cache_alloc_noprof() and kmalloc_noprof()\nand rely on current-\u003ealloc_tag having been set by the caller.  With\nCONFIG_MEM_ALLOC_PROFILING_DEBUG=y this leads to\n\n    current-\u003ealloc_tag not set\n    WARNING: ./include/linux/alloc_tag.h:161 at __alloc_tagging_slab_alloc_hook\n    alloc_tag was not set\n    WARNING: ./include/linux/alloc_tag.h:166 at __alloc_tagging_slab_free_hook\n\nat allocation and free time respectively, as reported when reading\nfiles on a CIFS mount.  The allocations are also missing from\n/proc/allocinfo.\n\nWrap the direct -\u003ealloc() invocations in alloc_hooks() with a new\nmempool_alloc_noreserve() helper in include/linux/mempool.h, next to\nthe other alloc_hooks()-wrapped macros such as mempool_alloc().  The\nGFP_KERNEL paths keep their failable allocation semantics, they just\nget tagged now.",
  "id": "GHSA-c3hx-25rr-8x92",
  "modified": "2026-10-23T15:31:30Z",
  "published": "2026-10-23T15:31:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98920"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/37a2042748bc880df03ff8315db86ed82991fbb8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5c03da745171485fd181f17b69213464f6d05f3d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b78b728e21c32ec4c330b299f657fb1eb02dffc2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-98920 (GCVE-0-2026-98920)

Vulnerability from cvelistv5 – Published: 2026-10-23 12:02 – Updated: 2026-10-23 12:05

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 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.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7061 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/5c03da745171485fd…
https://git.kernel.org/stable/c/37a2042748bc880df…
https://git.kernel.org/stable/c/b78b728e21c32ec4c…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 15ed8a9b7c63e9171f5139a6aaa1ffb61809861f , < 5c03da745171485fd181f17b69213464f6d05f3d (git) Affected: 1d78d56c43ef3768183e8370e7367b162700e049 , < 37a2042748bc880df03ff8315db86ed82991fbb8 (git) Affected: 1d78d56c43ef3768183e8370e7367b162700e049 , < b78b728e21c32ec4c330b299f657fb1eb02dffc2 (git) Affected: b343252d6f536203dd0660f676190dcbf6d2ecdc (git) Affected: 3f6d7f8a5416d852648d15a05e895f1195ee8a85 (git) Affected: 6.12.114 , < 6.13 (semver) Affected: 7.1.8 , < 7.2 (semver)
Linux	Linux	Affected: 7.2 Unaffected: 0 , < 7.2 (semver) Unaffected: 7.2.9 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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{
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Sightings

Author	Source	Type	Date	Other

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Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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