{"id":"CVE-2024-42293","summary":"arm64: mm: Fix lockless walks with static and dynamic page-table folding","details":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: mm: Fix lockless walks with static and dynamic page-table folding\n\nLina reports random oopsen originating from the fast GUP code when\n16K pages are used with 4-level page-tables, the fourth level being\nfolded at runtime due to lack of LPA2.\n\nIn this configuration, the generic implementation of\np4d_offset_lockless() will return a 'p4d_t *' corresponding to the\n'pgd_t' allocated on the stack of the caller, gup_fast_pgd_range().\nThis is normally fine, but when the fourth level of page-table is folded\nat runtime, pud_offset_lockless() will offset from the address of the\n'p4d_t' to calculate the address of the PUD in the same page-table page.\nThis results in a stray stack read when the 'p4d_t' has been allocated\non the stack and can send the walker into the weeds.\n\nFix the problem by providing our own definition of p4d_offset_lockless()\nwhen CONFIG_PGTABLE_LEVELS \u003c= 4 which returns the real page-table\npointer rather than the address of the local stack variable.","modified":"2026-04-02T12:17:55.497427Z","published":"2024-08-17T09:09:02.303Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/42xxx/CVE-2024-42293.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/36639013b3462c06ff8e3400a427f775b4fc97f5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/78672d49d3eebbcda3589f4d6e589caf357c5a59"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/42xxx/CVE-2024-42293.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-42293"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0dd4f60a2c76938c2625f6c630c225699d97608b"},{"fixed":"78672d49d3eebbcda3589f4d6e589caf357c5a59"},{"fixed":"36639013b3462c06ff8e3400a427f775b4fc97f5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-42293.json"}}],"schema_version":"1.7.5"}