ghsa-2jf2-9jhp-3fvx
Vulnerability from github
Published
2024-11-08 06:30
Modified
2024-11-08 18:30
Details

In the Linux kernel, the following vulnerability has been resolved:

mm/swapfile: skip HugeTLB pages for unuse_vma

I got a bad pud error and lost a 1GB HugeTLB when calling swapoff. The problem can be reproduced by the following steps:

  1. Allocate an anonymous 1GB HugeTLB and some other anonymous memory.
  2. Swapout the above anonymous memory.
  3. run swapoff and we will get a bad pud error in kernel message:

mm/pgtable-generic.c:42: bad pud 00000000743d215d(84000001400000e7)

We can tell that pud_clear_bad is called by pud_none_or_clear_bad in unuse_pud_range() by ftrace. And therefore the HugeTLB pages will never be freed because we lost it from page table. We can skip HugeTLB pages for unuse_vma to fix it.

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{
  "affected": [],
  "aliases": [
    "CVE-2024-50199"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-11-08T06:15:16Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/swapfile: skip HugeTLB pages for unuse_vma\n\nI got a bad pud error and lost a 1GB HugeTLB when calling swapoff.  The\nproblem can be reproduced by the following steps:\n\n 1. Allocate an anonymous 1GB HugeTLB and some other anonymous memory.\n 2. Swapout the above anonymous memory.\n 3. run swapoff and we will get a bad pud error in kernel message:\n\n  mm/pgtable-generic.c:42: bad pud 00000000743d215d(84000001400000e7)\n\nWe can tell that pud_clear_bad is called by pud_none_or_clear_bad in\nunuse_pud_range() by ftrace.  And therefore the HugeTLB pages will never\nbe freed because we lost it from page table.  We can skip HugeTLB pages\nfor unuse_vma to fix it.",
  "id": "GHSA-2jf2-9jhp-3fvx",
  "modified": "2024-11-08T18:30:50Z",
  "published": "2024-11-08T06:30:49Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-50199"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/417d5838ca73c6331ae2fe692fab6c25c00d9a0b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6ec0fe3756f941f42f8c57156b8bdf2877b2ebaf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7528c4fb1237512ee18049f852f014eba80bbe8d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ba7f982cdb37ff5a7739dec85d7325ea66fc1496"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bed2b9037806c62166a0ef9a559a1e7e3e1275b8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e41710f5a61aca9d6baaa8f53908a927dd9e7aa7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb66a833cdd2f7302ee05d05e0fa12a2ca32eb87"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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