cvelist/2024/40xxx/CVE-2024-40950.json

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        "ID": "CVE-2024-40950",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "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."
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
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    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Linux",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Linux",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "<",
                                            "version_name": "c010d47f107f",
                                            "version_value": "5df493a99fcf"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "6.9",
                                                        "status": "affected"
                                                    },
                                                    {
                                                        "version": "0",
                                                        "lessThan": "6.9",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
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                                                    {
                                                        "version": "6.9.7",
                                                        "lessThanOrEqual": "6.9.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
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                                                    {
                                                        "version": "6.10",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
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    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/5df493a99fcf887133cf01d23cd4bebb6d385d3c",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/5df493a99fcf887133cf01d23cd4bebb6d385d3c"
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                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/6a50c9b512f7734bc356f4bd47885a6f7c98491a"
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