LoongArch: Add DIRECT_MAP_PHYSMEM_END definition

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-93237
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-24 16:17:19 UTC
Updated2026-09-25 13:17:17 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: LoongArch: Add DIRECT_MAP_PHYSMEM_END definition get_free_mem_region() and mhp_get_pluggable_range() bound their search to DIRECT_MAP_PHYSMEM_END. LoongArch does not define it, so the fallback in include/linux/mm.h applies: under CONFIG_SPARSEMEM_VMEMMAP it is (1ULL << MAX_PHYSMEM_BITS) - 1, a compile-time constant that does not adapt to the CPU's physical address space bits (cpu_pabits, probed from CPUCFG1). The vmemmap window only covers physical space below 2^(cpu_pabits+1) (i.e. VMEMMAP_SIZE), so on CPUs with fewer physical address bits than MAX_PHYSMEM_BITS the fallback allows get_free_mem_region() to return a ZONE_DEVICE region outside the vmemmap window; vmemmap_populate() then wraps the memmap range around and maps it into low memory, silently corrupting the page tables. The same search also picked the top-of- address-space region that crashed memmap_init_zone_device() with amdkfd on Loongson-3C6000 in 6.16 [1]; the commit 2969b42c8f99 ("LoongArch/mm: align vmemmap to maximal folio size") keeps that region in bounds on current Loongson-3C6000 configs, but CPUs with smaller cpu_pabits (e.g. the Loongson-2K series) are still affected. Define DIRECT_MAP_PHYSMEM_END as the vmemmap-covered physical range, (1ULL << (cpu_pabits + 1)) - 1, capped at (1ULL << MAX_PHYSMEM_BITS) - 1 under CONFIG_SPARSEMEM, similar to the commit f3336b48cf9d ("riscv: mm: Define DIRECT_MAP_PHYSMEM_END"). [1] https://lore.kernel.org/amd-gfx/[email protected]/

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001730000 probability, percentile 0.060130000 (date 2026-09-27)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 7b09f5af01ede480cbe7abcb281cf17550a46ff5 ab275a23b4d9f04ca6c2f5f6a3246194e045a761 git Not specified
CNA Linux Linux affected 7b09f5af01ede480cbe7abcb281cf17550a46ff5 55e18311c705cceef6c34d522ea387b1f0069bab git Not specified
CNA Linux Linux affected 7b09f5af01ede480cbe7abcb281cf17550a46ff5 2677f97a67fdbc62a82ce1faa67791f54451d36f git Not specified
CNA Linux Linux affected 6.2 Not specified
CNA Linux Linux unaffected 6.2 semver Not specified
CNA Linux Linux unaffected 6.18.51 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.5 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/ab275a23b4d9f04ca6c2f5f6a3246194e045a761 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/55e18311c705cceef6c34d522ea387b1f0069bab 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2677f97a67fdbc62a82ce1faa67791f54451d36f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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