FKIE_CVE-2026-93216

Vulnerability from fkie_nvd - Published: 2026-09-24 16:17 - Updated: 2026-09-24 16:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg() print_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the start to guard against tail pages and NULL data. However, it later re-reads page->memcg_data locklessly in two places: 1: page_memcg_check(page) 2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS) If the page is concurrently freed and reallocated as a THP tail page or slab page between these calls, the VM_BUG_ON assertions can trigger on CONFIG_DEBUG_VM=y builds, crashing the kernel. Fix both TOCTOU issues by using the memcg_data snapshot throughout.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/46761406e14381dc35f498c247a87565b87ea2ef
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/90f095b816e25c6a9e4446d299bac5007fdcb3df
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/page_owner.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "46761406e14381dc35f498c247a87565b87ea2ef",
              "status": "affected",
              "version": "fcf8935832b86d3437f00e732c6d0d4d2819d6a9",
              "versionType": "git"
            },
            {
              "lessThan": "90f095b816e25c6a9e4446d299bac5007fdcb3df",
              "status": "affected",
              "version": "fcf8935832b86d3437f00e732c6d0d4d2819d6a9",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/page_owner.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg()\n\nprint_page_owner_memcg() reads page-\u003ememcg_data via READ_ONCE() at the\nstart to guard against tail pages and NULL data.  However, it later\nre-reads page-\u003ememcg_data locklessly in two places:\n\n1: page_memcg_check(page)\n\n2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes\n   VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS)\n\nIf the page is concurrently freed and reallocated as a THP tail page or\nslab page between these calls, the VM_BUG_ON assertions can trigger on\nCONFIG_DEBUG_VM=y builds, crashing the kernel.\n\nFix both TOCTOU issues by using the memcg_data snapshot throughout."
    }
  ],
  "id": "CVE-2026-93216",
  "lastModified": "2026-09-24T16:17:16.670",
  "metrics": {},
  "published": "2026-09-24T16:17:16.670",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/46761406e14381dc35f498c247a87565b87ea2ef"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/90f095b816e25c6a9e4446d299bac5007fdcb3df"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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