{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-40006",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2025-40006"
  ],
  "published": "2025-10-20T15:27:24Z",
  "summary": "mm/hugetlb: fix folio is still mapped when deleted",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/hugetlb: fix folio is still mapped when deleted\n\nMigration may be raced with fallocating hole.  remove_inode_single_folio\nwill unmap the folio if the folio is still mapped.  However, it's called\nwithout folio lock.  If the folio is migrated and the mapped pte has been\nconverted to migration entry, folio_mapped() returns false, and won't\nunmap it.  Due to extra refcount held by remove_inode_single_folio,\nmigration fails, restores migration entry to normal pte, and the folio is\nmapped again.  As a result, we triggered BUG in filemap_unaccount_folio.\n\nThe log is as follows:\n BUG: Bad page cache in process hugetlb  pfn:156c00\n page: refcount:515 mapcount:0 mapping:0000000099fef6e1 index:0x0 pfn:0x156c00\n head: order:9 mapcount:1 entire_mapcount:1 nr_pages_mapped:0 pincount:0\n aops:hugetlbfs_aops ino:dcc dentry name(?):\"my_hugepage_file\"\n flags: 0x17ffffc00000c1(locked|waiters|head|node=0|zone=2|lastcpupid=0x1fffff)\n page_type: f4(hugetlb)\n page dumped because: still mapped when deleted\n CPU: 1 UID: 0 PID: 395 Comm: hugetlb Not tainted 6.17.0-rc5-00044-g7aac71907bde-dirty #484 NONE\n Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015\n Call Trace:\n  <TASK>\n  dump_stack_lvl+0x4f/0x70\n  filemap_unaccount_folio+0xc4/0x1c0\n  __filemap_remove_folio+0x38/0x1c0\n  filemap_remove_folio+0x41/0xd0\n  remove_inode_hugepages+0x142/0x250\n  hugetlbfs_fallocate+0x471/0x5a0\n  vfs_fallocate+0x149/0x380\n\nHold folio lock before checking if the folio is mapped to avold race with\nmigration.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.155",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-40006"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/bc1c9ce8aeff45318332035dbef9713fb9e982d7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/91f548e920fbf8be3f285bfa3fa045ae017e836d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3e851448078f5b01f6264915df3cfef75e323a12"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c1dc0524ab2cc3982d4e0d2bfac71a0cd4d65c39"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c9c2a51f91aea70e89b496cac360cd795a2b3c26"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/910d7749346c4b0acdc6e4adfdc4a9984281a206"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/21ee79ce938127f88fe07e409c1817f477dbe7ea"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7b7387650dcf2881fd8bb55bcf3c8bd6c9542dd7"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T12:19:11Z"
  }
}