{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: khugepaged: skip huge page collapse for special files\n\nThe read-only THP for filesystems will collapse THP for files opened\nreadonly and mapped with VM_EXEC.  The intended usecase is to avoid TLB\nmisses for large text segments.  But it doesn't restrict the file types\nso a THP could be collapsed for a non-regular file, for example, block\ndevice, if it is opened readonly and mapped with EXEC permission.  This\nmay cause bugs, like [1] and [2].\n\nThis is definitely not the intended usecase, so just collapse THP for\nregular files in order to close the attack surface.\n\n[shy828301@gmail.com: fix vm_file check [3]]"
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "mm/khugepaged.c"
               ],
               "versions": [
                  {
                     "version": "99cb0dbd47a1",
                     "lessThan": "6d67b2a73b8e",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "99cb0dbd47a1",
                     "lessThan": "5fcb6fce74ff",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "99cb0dbd47a1",
                     "lessThan": "a4aeaa06d45e",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "mm/khugepaged.c"
               ],
               "versions": [
                  {
                     "version": "5.4",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "5.4",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.10.78",
                     "lessThanOrEqual": "5.10.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.14.16",
                     "lessThanOrEqual": "5.14.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/6d67b2a73b8e3a079c355bab3c1aef7d85a044b8"
            },
            {
               "url": "https://git.kernel.org/stable/c/5fcb6fce74ffa614d964667110cf1a516c48c6d9"
            },
            {
               "url": "https://git.kernel.org/stable/c/a4aeaa06d45e90f9b279f0b09de84bd00006e733"
            }
         ],
         "title": "mm: khugepaged: skip huge page collapse for special files",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2021-47491",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}