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

Vulnerability from cvelistv5 – Published: 2026-10-23 12:02 – Updated: 2026-10-23 12:05
VLAI
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 6653 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
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)
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Linux Linux Affected: 7.2
Unaffected: 0 , < 7.2 (semver)
Unaffected: 7.2.9 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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          "value": "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."
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        {
          "url": "https://git.kernel.org/stable/c/b78b728e21c32ec4c330b299f657fb1eb02dffc2"
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      "title": "netfs: Fix missing alloc tagging of direct mempool allocations",
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    "cveId": "CVE-2026-98920",
    "datePublished": "2026-10-23T12:02:06.560Z",
    "dateReserved": "2026-09-25T10:25:14.380Z",
    "dateUpdated": "2026-10-23T12:05:25.919Z",
    "state": "PUBLISHED"
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            "value": "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."
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        "id": "CVE-2026-98920",
        "lastModified": "2026-10-23T13:17:12.617",
        "metrics": {},
        "published": "2026-10-23T13:17:12.617",
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      "cve": "CVE-2026-98920",
      "id": "CVE-2026-98920",
      "initial_release_date": "2026-10-23T00:00:00+00:00",
      "product_status:known_affected": "1",
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: netfs: Fix missing alloc tagging of direct mempool allocations",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98920.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "low",
      "current_release_date": "2026-10-27T18:00:07Z",
      "cve": "CVE-2026-98920",
      "id": "CVE-2026-98920",
      "initial_release_date": "2026-10-27T18:00:07Z",
      "product_status:known_affected": "30",
      "product_status:known_not_affected": "318",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-98920",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-98920.json",
      "version": "2"
    }
  }
}



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