{"id":"CVE-2026-93232","state":"PUBLISHED","title":"mm/hugetlb: fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/hugetlb: fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages\n\nPatch series \"mm: Refactor bootmem gigantic hugepage allocation\", v4.\n\nThis series is split out from the earlier larger series \"mm: Generalize\nHVO for HugeTLB and device DAX\" [1].  It collects the first 19 patches of\nthat series as a standalone set of fixes and preparatory cleanups around\nbootmem HugeTLB handling, sparse initialization ordering, and related\nvmemmap setup.\n\nThe first patches fix a few bugs found while reviewing the existing code,\nincluding incorrect bootmem HVO handling, wrong vmemmap registration\narguments, a powerpc compound-vmemmap tracking bug, and too-late\ninitialization of gigantic bootmem HugeTLB struct pages.\n\nThe rest of the series reorders early memory initialization so the\nrelevant zone state is available before sparse and HugeTLB boot-time setup\nruns, then simplifies the remaining bootmem gigantic hugepage allocation\npath and removes code made obsolete by that rework.\n\nAt a high level:\n  - patches [1-4] fix boot-time and arch-specific bugs\n  - patches [5-12] reorder and simplify sparse/mm/hugetlb early init\n  - patches [13-19] refactor bootmem gigantic hugepage allocation and\n    remove obsolete helpers and state\n\n\nThis patch (of 19):\n\nCommit 622026e87c40 (\"mm/hugetlb: remove fake head pages\") switched\nHVO to reuse per-zone shared tail pages from zone->vmemmap_tails[].\n\nThose shared tail pages were initialized in hugetlb_vmemmap_init(), but\nbootmem HugeTLB folios are prepared earlier from\ngather_bootmem_prealloc().  With hugetlb_free_vmemmap=on,\nprep_and_add_bootmem_folios() can access pageblock flags on bootmem\nHugeTLB pages whose mirrored tail struct pages already point to the shared\ntail page.  On CONFIG_DEBUG_VM kernels, get_pfnblock_bitmap_bitidx() then\ndereferences the still-uninitialized shared tail page and can panic during\nboot.\n\nInitialize zone->vmemmap_tails[] from gather_bootmem_prealloc(), before\nbootmem HugeTLB folios are processed, and drop the later initialization\nfrom hugetlb_vmemmap_init().\n\nThis bug only affects CONFIG_DEBUG_VM kernels, where the relevant\nassertion is evaluated.","publishedAt":"2026-09-24T15:29:22.699Z","updatedAt":"2026-10-19T09:07:43.993Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"622026e87c4019e609010811757e31193cc23847","status":"affected","lessThan":"2ddf429e25cf8415d9c308f07e64012026bd4d77","versionType":"git"},{"version":"622026e87c4019e609010811757e31193cc23847","status":"affected","lessThan":"c0caeceb0c3899dc42844d3979093b27d1434108","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/hugetlb.c","mm/hugetlb_vmemmap.c","mm/sparse-vmemmap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/hugetlb.c","mm/hugetlb_vmemmap.c","mm/sparse-vmemmap.c"]}],"references":["https://git.kernel.org/stable/c/2ddf429e25cf8415d9c308f07e64012026bd4d77","https://git.kernel.org/stable/c/c0caeceb0c3899dc42844d3979093b27d1434108"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/93xxx/CVE-2026-93232.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93232","state":"PUBLISHED","datePublished":"2026-09-24T15:29:22.699Z","dateUpdated":"2026-10-19T09:07:43.993Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-17T16:02:15.095Z"},"containers":{"cna":{"title":"mm/hugetlb: fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/hugetlb: fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages\n\nPatch series \"mm: Refactor bootmem gigantic hugepage allocation\", v4.\n\nThis series is split out from the earlier larger series \"mm: Generalize\nHVO for HugeTLB and device DAX\" [1].  It collects the first 19 patches of\nthat series as a standalone set of fixes and preparatory cleanups around\nbootmem HugeTLB handling, sparse initialization ordering, and related\nvmemmap setup.\n\nThe first patches fix a few bugs found while reviewing the existing code,\nincluding incorrect bootmem HVO handling, wrong vmemmap registration\narguments, a powerpc compound-vmemmap tracking bug, and too-late\ninitialization of gigantic bootmem HugeTLB struct pages.\n\nThe rest of the series reorders early memory initialization so the\nrelevant zone state is available before sparse and HugeTLB boot-time setup\nruns, then simplifies the remaining bootmem gigantic hugepage allocation\npath and removes code made obsolete by that rework.\n\nAt a high level:\n  - patches [1-4] fix boot-time and arch-specific bugs\n  - patches [5-12] reorder and simplify sparse/mm/hugetlb early init\n  - patches [13-19] refactor bootmem gigantic hugepage allocation and\n    remove obsolete helpers and state\n\n\nThis patch (of 19):\n\nCommit 622026e87c40 (\"mm/hugetlb: remove fake head pages\") switched\nHVO to reuse per-zone shared tail pages from zone->vmemmap_tails[].\n\nThose shared tail pages were initialized in hugetlb_vmemmap_init(), but\nbootmem HugeTLB folios are prepared earlier from\ngather_bootmem_prealloc().  With hugetlb_free_vmemmap=on,\nprep_and_add_bootmem_folios() can access pageblock flags on bootmem\nHugeTLB pages whose mirrored tail struct pages already point to the shared\ntail page.  On CONFIG_DEBUG_VM kernels, get_pfnblock_bitmap_bitidx() then\ndereferences the still-uninitialized shared tail page and can panic during\nboot.\n\nInitialize zone->vmemmap_tails[] from gather_bootmem_prealloc(), before\nbootmem HugeTLB folios are processed, and drop the later initialization\nfrom hugetlb_vmemmap_init().\n\nThis bug only affects CONFIG_DEBUG_VM kernels, where the relevant\nassertion is evaluated."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"622026e87c4019e609010811757e31193cc23847","status":"affected","lessThan":"2ddf429e25cf8415d9c308f07e64012026bd4d77","versionType":"git"},{"version":"622026e87c4019e609010811757e31193cc23847","status":"affected","lessThan":"c0caeceb0c3899dc42844d3979093b27d1434108","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/hugetlb.c","mm/hugetlb_vmemmap.c","mm/sparse-vmemmap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/hugetlb.c","mm/hugetlb_vmemmap.c","mm/sparse-vmemmap.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/2ddf429e25cf8415d9c308f07e64012026bd4d77"},{"url":"https://git.kernel.org/stable/c/c0caeceb0c3899dc42844d3979093b27d1434108"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:07:43.993Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}