{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "52526ca7fdb905a768a93f8faa418e9b988fc34b"
            },
            {
              "fixed": "a6ac03652d9edc30c2912037ac83beb42cc67f8e"
            },
            {
              "fixed": "43b987ed35be9be21a303d1036d4241fec9943df"
            },
            {
              "fixed": "18b8a9700610299819d21fd0ea85d24726d17f65"
            },
            {
              "fixed": "e92d92bbafb264dc0518d52b846a3c07ed8d523f"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72174.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole()\n\nA PAGEMAP_SCAN ioctl requesting PM_SCAN_WP_MATCHING on a hugetlb VMA hangs\nthe calling thread, unkillably, as soon as the scan reaches an unpopulated\npart of the range:\n\n  do_pagemap_scan()\n    walk_page_range()\n      walk_hugetlb_range()\n        hugetlb_vma_lock_read()           # take the vma lock for read ...\n        pagemap_scan_pte_hole()           # ... -\u003epte_hole() for a hole\n          uffd_wp_range()\n            change_protection()\n              hugetlb_change_protection()\n                hugetlb_vma_lock_write()  # ... and block taking it for write\n\nwalk_hugetlb_range() holds the hugetlb vma lock for read across the whole\nwalk.  A present entry goes to -\u003ehugetlb_entry(); an unpopulated one goes\nto -\u003epte_hole(), i.e.  pagemap_scan_pte_hole().  To write-protect the hole\nthat handler calls uffd_wp_range(), which on a hugetlb VMA reaches\nhugetlb_change_protection() and takes the same vma lock for write.  The\nthread then blocks in down_write() waiting for the read lock it is itself\nholding.\n\nThe populated path avoids this: pagemap_scan_hugetlb_entry()\nwrite-protects the entry inline under the page-table lock and never enters\nhugetlb_change_protection().\n\nDo the same for holes.  Fault in the page table and install the uffd-wp\nmarker directly with make_uffd_wp_huge_pte() under the page-table lock,\nrather than routing through uffd_wp_range().  That is the same sequence\nhugetlb_change_protection() runs for an unpopulated entry, minus the vma\nwrite lock -- which is safe to skip because PMD sharing is disabled on\nuffd-wp VMAs (hugetlb_unshare_all_pmds() runs at registration), leaving\nnothing for that lock to serialise against.",
  "id": "CVE-2026-72174",
  "modified": "2026-08-18T03:31:08.613428073Z",
  "published": "2026-08-15T05:53:39.276Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/18b8a9700610299819d21fd0ea85d24726d17f65"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/43b987ed35be9be21a303d1036d4241fec9943df"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a6ac03652d9edc30c2912037ac83beb42cc67f8e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e92d92bbafb264dc0518d52b846a3c07ed8d523f"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72174.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72174"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole()"
}