CVE-2025-40288
Estado: AplazadaSin puntuar—
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: Fix NULL pointer dereference in VRAM logic for APU devices
Previously, APU platforms (and other scenarios with uninitialized VRAM managers) triggered a NULL pointer dereference in `ttm_resource_manager_usage()`. The root cause is not that the `struct ttm_resource_manager *man` pointer itself is NULL, but that `man->bdev` (the backing device pointer within the manager) remains uninitialized (NULL) on APUs—since APUs lack dedicated VRAM and do not fully set up VRAM manager structures. When `ttm_resource_manager_usage()` attempts to acquire `man->bdev->lru_lock`, it dereferences the NULL `man->bdev`, leading to a kernel OOPS.
Leer descripción completaMostrar menos
This approach is more robust than APU-specific checks because it: - Works for all scenarios where the VRAM manager is uninitialized (not just APUs), - Aligns with TTM's design by using its native helper function, - Preserves correct behavior for discrete GPUs (which have fully initialized `man->bdev` and pass the `ttm_resource_manager_used()` check).
v4: use ttm_resource_manager_used(&adev->mman.vram_mgr.manager) instead of checking the adev->gmc.is_app_apu flag (Christian)
Detalles técnicos trazas, registros y código del informe original
1. **amdgpu_cs.c**: Extend the existing bandwidth control check in `amdgpu_cs_get_threshold_for_moves()` to include a check for `ttm_resource_manager_used()`. If the manager is not used (uninitialized `bdev`), return 0 for migration thresholds immediately—skipping VRAM-specific logic that would trigger the NULL dereference. 2. **amdgpu_kms.c**: Update the `AMDGPU_INFO_VRAM_USAGE` ioctl and memory info reporting to use a conditional: if the manager is used, return the real VRAM usage; otherwise, return 0. This avoids accessing `man->bdev` when it is NULL. 3. **amdgpu_virt.c**: Modify the vf2pf (virtual function to physical function) data write path. Use `ttm_resource_manager_used()` to check validity: if the manager is usable, calculate `fb_usage` from VRAM usage; otherwise, set `fb_usage` to 0 (APUs have no discrete framebuffer to report).
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.19%
- Percentil entre todas las CVEs puntuadas: 7
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/070bdce18fb12a49eb9c421e57df17d2ad29bf5f
- https://git.kernel.org/stable/c/1243e396148a65bb6c42a2b70fe43e50c16c494f
- https://git.kernel.org/stable/c/43aa61c18a3a45042b098b7a1186ffb29364002c
- https://git.kernel.org/stable/c/883f309add55060233bf11c1ea6947140372920f
- https://git.kernel.org/stable/c/e70113b741ba253886cd71dbadfe3ea444bb2f5c
JSON original (NVD)
Mostrar
{
"id": "CVE-2025-40288",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
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"vendor": "Linux",
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"versions": [
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"status": "affected",
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"programFiles": [
"drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c",
"drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c",
"drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.2"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.2",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.159",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.117",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
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{
"status": "unaffected",
"version": "6.12.59",
"versionType": "semver",
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{
"status": "unaffected",
"version": "6.17.9",
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{
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"version": "6.18",
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"programFiles": [
"drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c",
"drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c",
"drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c"
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"defaultStatus": "affected"
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}
],
"published": "2025-12-06T22:15:57.067",
"references": [
{
"url": "https://git.kernel.org/stable/c/070bdce18fb12a49eb9c421e57df17d2ad29bf5f",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Deferred",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu: Fix NULL pointer dereference in VRAM logic for APU devices\n\nPreviously, APU platforms (and other scenarios with uninitialized VRAM managers)\ntriggered a NULL pointer dereference in `ttm_resource_manager_usage()`. The root\ncause is not that the `struct ttm_resource_manager *man` pointer itself is NULL,\nbut that `man->bdev` (the backing device pointer within the manager) remains\nuninitialized (NULL) on APUs—since APUs lack dedicated VRAM and do not fully\nset up VRAM manager structures. When `ttm_resource_manager_usage()` attempts to\nacquire `man->bdev->lru_lock`, it dereferences the NULL `man->bdev`, leading to\na kernel OOPS.\n\n1. **amdgpu_cs.c**: Extend the existing bandwidth control check in\n `amdgpu_cs_get_threshold_for_moves()` to include a check for\n `ttm_resource_manager_used()`. If the manager is not used (uninitialized\n `bdev`), return 0 for migration thresholds immediately—skipping VRAM-specific\n logic that would trigger the NULL dereference.\n\n2. **amdgpu_kms.c**: Update the `AMDGPU_INFO_VRAM_USAGE` ioctl and memory info\n reporting to use a conditional: if the manager is used, return the real VRAM\n usage; otherwise, return 0. This avoids accessing `man->bdev` when it is\n NULL.\n\n3. **amdgpu_virt.c**: Modify the vf2pf (virtual function to physical function)\n data write path. Use `ttm_resource_manager_used()` to check validity: if the\n manager is usable, calculate `fb_usage` from VRAM usage; otherwise, set\n `fb_usage` to 0 (APUs have no discrete framebuffer to report).\n\nThis approach is more robust than APU-specific checks because it:\n- Works for all scenarios where the VRAM manager is uninitialized (not just APUs),\n- Aligns with TTM's design by using its native helper function,\n- Preserves correct behavior for discrete GPUs (which have fully initialized\n `man->bdev` and pass the `ttm_resource_manager_used()` check).\n\nv4: use ttm_resource_manager_used(&adev->mman.vram_mgr.manager) instead of checking the adev->gmc.is_app_apu flag (Christian)"
}
],
"lastModified": "2026-06-17T09:21:36.077",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}