CVE-2026-68436 (GCVE-0-2026-68436)
Vulnerability from cvelistv5
Published
2026-08-12 00:07
Modified
2026-08-18 06:56
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: use kvzalloc to allocate struct dc
struct dc has grown large over time (most of it the two inlined
dc_scratch_space copies) and now sits close to the page allocator's 4 MiB
contiguous allocation limit. Its actual size is not fixed by the source
alone, it also depends on the compiler and the .config, so it can easily
cross 4 MiB, e.g. with a newer GCC or a config change.
dc_create() allocates it with kzalloc(). Once struct dc exceeds 4 MiB the
request is rounded up to order 11 (8 MiB), which is above MAX_PAGE_ORDER,
so the page allocator warns and returns NULL. dc_create() then fails, DM
init fails and amdgpu probe aborts with -EINVAL:
WARNING: mm/page_alloc.c:5197 at __alloc_frozen_pages_noprof+0x2f9/0x380
dc_create+0x38/0x660 [amdgpu]
amdgpu_dm_init+0x2d9/0x510 [amdgpu]
dm_hw_init+0x1b/0x90 [amdgpu]
amdgpu_device_init.cold+0x150d/0x1e13 [amdgpu]
amdgpu_driver_load_kms+0x19/0x80 [amdgpu]
amdgpu_pci_probe+0x1e2/0x4c0 [amdgpu]
dc_create() then returns NULL and DM init fails, which aborts the whole
GPU init and makes amdgpu probe fail with -EINVAL ("hw_init of IP block
<dm> failed -22"), leaving the display unusable. The subsequent
amdgpu_irq_put() warnings during teardown are just fallout of unwinding
a half-initialized device.
struct dc is a software-only bookkeeping structure that is never handed
to hardware DMA and is only ever kept as an opaque pointer, so it does
not require physically contiguous memory. Allocate it with kvzalloc()
(and free it with kvfree()) so that the allocator can fall back to
vmalloc() when a contiguous allocation of that size is not available,
which also avoids the MAX_PAGE_ORDER warning entirely.
v2:
- Rebase to amd-staging-drm-next.
(cherry picked from commit 991e0516a8072f2292681c6ae98a924ab0e32575)
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/gpu/drm/amd/display/dc/core/dc.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "dbad70d40cad9c5e7586953275287fe7531fb811",
"status": "affected",
"version": "d62d5551dd615f9e488b13595d69b308cd019e16",
"versionType": "git"
},
{
"lessThan": "75050390151a14802be433c3856ddcb483cecd24",
"status": "affected",
"version": "d62d5551dd615f9e488b13595d69b308cd019e16",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/gpu/drm/amd/display/dc/core/dc.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.10"
},
{
"lessThan": "6.10",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.6",
"versionStartIncluding": "6.10",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.10",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: use kvzalloc to allocate struct dc\n\nstruct dc has grown large over time (most of it the two inlined\ndc_scratch_space copies) and now sits close to the page allocator\u0027s 4 MiB\ncontiguous allocation limit. Its actual size is not fixed by the source\nalone, it also depends on the compiler and the .config, so it can easily\ncross 4 MiB, e.g. with a newer GCC or a config change.\n\ndc_create() allocates it with kzalloc(). Once struct dc exceeds 4 MiB the\nrequest is rounded up to order 11 (8 MiB), which is above MAX_PAGE_ORDER,\nso the page allocator warns and returns NULL. dc_create() then fails, DM\ninit fails and amdgpu probe aborts with -EINVAL:\n\n WARNING: mm/page_alloc.c:5197 at __alloc_frozen_pages_noprof+0x2f9/0x380\n dc_create+0x38/0x660 [amdgpu]\n amdgpu_dm_init+0x2d9/0x510 [amdgpu]\n dm_hw_init+0x1b/0x90 [amdgpu]\n amdgpu_device_init.cold+0x150d/0x1e13 [amdgpu]\n amdgpu_driver_load_kms+0x19/0x80 [amdgpu]\n amdgpu_pci_probe+0x1e2/0x4c0 [amdgpu]\n\ndc_create() then returns NULL and DM init fails, which aborts the whole\nGPU init and makes amdgpu probe fail with -EINVAL (\"hw_init of IP block\n\u003cdm\u003e failed -22\"), leaving the display unusable. The subsequent\namdgpu_irq_put() warnings during teardown are just fallout of unwinding\na half-initialized device.\n\nstruct dc is a software-only bookkeeping structure that is never handed\nto hardware DMA and is only ever kept as an opaque pointer, so it does\nnot require physically contiguous memory. Allocate it with kvzalloc()\n(and free it with kvfree()) so that the allocator can fall back to\nvmalloc() when a contiguous allocation of that size is not available,\nwhich also avoids the MAX_PAGE_ORDER warning entirely.\n\nv2:\n - Rebase to amd-staging-drm-next.\n\n(cherry picked from commit 991e0516a8072f2292681c6ae98a924ab0e32575)"
}
],
"providerMetadata": {
"dateUpdated": "2026-08-18T06:56:03.101Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/dbad70d40cad9c5e7586953275287fe7531fb811"
},
{
"url": "https://git.kernel.org/stable/c/75050390151a14802be433c3856ddcb483cecd24"
}
],
"title": "drm/amd/display: use kvzalloc to allocate struct dc",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-68436",
"datePublished": "2026-08-12T00:07:24.698Z",
"dateReserved": "2026-07-30T09:28:09.394Z",
"dateUpdated": "2026-08-18T06:56:03.101Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…