{"id":"CVE-2026-93237","summary":"LoongArch: Add DIRECT_MAP_PHYSMEM_END definition","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Add DIRECT_MAP_PHYSMEM_END definition\n\nget_free_mem_region() and mhp_get_pluggable_range() bound their search\nto DIRECT_MAP_PHYSMEM_END. LoongArch does not define it, so the fallback\nin include/linux/mm.h applies: under CONFIG_SPARSEMEM_VMEMMAP it is\n(1ULL \u003c\u003c MAX_PHYSMEM_BITS) - 1, a compile-time constant that does not\nadapt to the CPU's physical address space bits (cpu_pabits, probed from\nCPUCFG1).\n\nThe vmemmap window only covers physical space below 2^(cpu_pabits+1)\n(i.e. VMEMMAP_SIZE), so on CPUs with fewer physical address bits than\nMAX_PHYSMEM_BITS the fallback allows get_free_mem_region() to return\na ZONE_DEVICE region outside the vmemmap window; vmemmap_populate() then\nwraps the memmap range around and maps it into low memory, silently\ncorrupting the page tables. The same search also picked the top-of-\naddress-space region that crashed memmap_init_zone_device() with amdkfd\non Loongson-3C6000 in 6.16 [1]; the commit 2969b42c8f99 (\"LoongArch/mm:\nalign vmemmap to maximal folio size\") keeps that region in bounds on\ncurrent Loongson-3C6000 configs, but CPUs with smaller cpu_pabits (e.g.\nthe Loongson-2K series) are still affected.\n\nDefine DIRECT_MAP_PHYSMEM_END as the vmemmap-covered physical range,\n(1ULL \u003c\u003c (cpu_pabits + 1)) - 1, capped at (1ULL \u003c\u003c MAX_PHYSMEM_BITS) - 1\nunder CONFIG_SPARSEMEM, similar to the commit f3336b48cf9d (\"riscv: mm:\nDefine DIRECT_MAP_PHYSMEM_END\").\n\n[1] https://lore.kernel.org/amd-gfx/20250814032153.227285-1-jeffbai@aosc.io/","modified":"2026-09-29T18:26:48.176447842Z","published":"2026-09-24T15:33:51.702Z","related":["openSUSE-SU-2026:11893-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93237.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2677f97a67fdbc62a82ce1faa67791f54451d36f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/55e18311c705cceef6c34d522ea387b1f0069bab"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ab275a23b4d9f04ca6c2f5f6a3246194e045a761"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93237.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93237"},{"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":"7b09f5af01ede480cbe7abcb281cf17550a46ff5"},{"fixed":"ab275a23b4d9f04ca6c2f5f6a3246194e045a761"},{"fixed":"55e18311c705cceef6c34d522ea387b1f0069bab"},{"fixed":"2677f97a67fdbc62a82ce1faa67791f54451d36f"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-93237.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.18.51"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-93237.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}