cve/published/2024/CVE-2024-40950.json

{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
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         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: huge_memory: fix misused mapping_large_folio_support() for anon folios\n\nWhen I did a large folios split test, a WARNING \"[ 5059.122759][ T166]\nCannot split file folio to non-0 order\" was triggered.  But the test cases\nare only for anonmous folios.  while mapping_large_folio_support() is only\nreasonable for page cache folios.\n\nIn split_huge_page_to_list_to_order(), the folio passed to\nmapping_large_folio_support() maybe anonmous folio.  The folio_test_anon()\ncheck is missing.  So the split of the anonmous THP is failed.  This is\nalso the same for shmem_mapping().  We'd better add a check for both.  But\nthe shmem_mapping() in __split_huge_page() is not involved, as for\nanonmous folios, the end parameter is set to -1, so (head[i].index >= end)\nis always false.  shmem_mapping() is not called.\n\nAlso add a VM_WARN_ON_ONCE() in mapping_large_folio_support() for anon\nmapping, So we can detect the wrong use more easily.\n\nTHP folios maybe exist in the pagecache even the file system doesn't\nsupport large folio, it is because when CONFIG_TRANSPARENT_HUGEPAGE is\nenabled, khugepaged will try to collapse read-only file-backed pages to\nTHP.  But the mapping does not actually support multi order large folios\nproperly.\n\nUsing /sys/kernel/debug/split_huge_pages to verify this, with this patch,\nlarge anon THP is successfully split and the warning is ceased."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "include/linux/pagemap.h",
                  "mm/huge_memory.c"
               ],
               "versions": [
                  {
                     "version": "c010d47f107f609b9f4d6a103b6dfc53889049e9",
                     "lessThan": "5df493a99fcf887133cf01d23cd4bebb6d385d3c",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "c010d47f107f609b9f4d6a103b6dfc53889049e9",
                     "lessThan": "6a50c9b512f7734bc356f4bd47885a6f7c98491a",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "include/linux/pagemap.h",
                  "mm/huge_memory.c"
               ],
               "versions": [
                  {
                     "version": "6.9",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "6.9",
                     "status": "unaffected",
                     "versionType": "semver"
                  },
                  {
                     "version": "6.9.7",
                     "lessThanOrEqual": "6.9.*",
                     "status": "unaffected",
                     "versionType": "semver"
                  },
                  {
                     "version": "6.10",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "cpeApplicability": [
            {
               "nodes": [
                  {
                     "operator": "OR",
                     "negate": false,
                     "cpeMatch": [
                        {
                           "vulnerable": true,
                           "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                           "versionStartIncluding": "6.9",
                           "versionEndExcluding": "6.9.7"
                        },
                        {
                           "vulnerable": true,
                           "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                           "versionStartIncluding": "6.9",
                           "versionEndExcluding": "6.10"
                        }
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         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/5df493a99fcf887133cf01d23cd4bebb6d385d3c"
            },
            {
               "url": "https://git.kernel.org/stable/c/6a50c9b512f7734bc356f4bd47885a6f7c98491a"
            }
         ],
         "title": "mm: huge_memory: fix misused mapping_large_folio_support() for anon folios",
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   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-40950",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
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