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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