Medium [CVE-2026-68436] use kvzalloc to allocate struct dc
This medium-severity Red Hat Linux advisory covers CVE-2026-68436 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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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 failed -22"), leaving the display unusable.
Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; and 4 more.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 3 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 3 hours ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 3 hours ago·verify at source
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