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    "CVE_data_meta": {
        "ID": "CVE-2021-47491",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "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]]"
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
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        ]
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    "affects": {
        "vendor": {
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                    "vendor_name": "Linux",
                    "product": {
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                                "product_name": "Linux",
                                "version": {
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                                            "version_name": "99cb0dbd47a1",
                                            "version_value": "6d67b2a73b8e"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "5.4",
                                                        "status": "affected"
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                                                        "version": "0",
                                                        "lessThan": "5.4",
                                                        "status": "unaffected",
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                                                    {
                                                        "version": "5.10.78",
                                                        "lessThanOrEqual": "5.10.*",
                                                        "status": "unaffected",
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                                                    {
                                                        "version": "5.14.16",
                                                        "lessThanOrEqual": "5.14.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
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                                                    {
                                                        "version": "5.15",
                                                        "lessThanOrEqual": "*",
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                                                        "versionType": "original_commit_for_fix"
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                "url": "https://git.kernel.org/stable/c/6d67b2a73b8e3a079c355bab3c1aef7d85a044b8",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/6d67b2a73b8e3a079c355bab3c1aef7d85a044b8"
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                "url": "https://git.kernel.org/stable/c/5fcb6fce74ffa614d964667110cf1a516c48c6d9",
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                "name": "https://git.kernel.org/stable/c/5fcb6fce74ffa614d964667110cf1a516c48c6d9"
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