CVE-2026-43280drm/xe: Add bounds check on pat_index to prevent OOB kernel read in madvise

Official description

In the Linux kernel, the following vulnerability has been resolved: drm/xe: Add bounds check on pat_index to prevent OOB kernel read in madvise When user provides a bogus pat_index value through the madvise IOCTL, the xe_pat_index_get_coh_mode() function performs an array access without validating bounds. This allows a malicious user to trigger an out-of-bounds kernel read from the xe->pat.table array. The vulnerability exists because the validation in madvise_args_are_sane() directly calls xe_pat_index_get_coh_mode(xe, args->pat_index.val) without first checking if pat_index is within [0, xe->pat.n_entries). Although xe_pat_index_get_coh_mode() has a WARN_ON to catch this in debug builds, it still performs the unsafe array access in production kernels. v2(Matthew Auld) - Using array_index_nospec() to mitigate spectre attacks when the value is used v3(Matthew Auld) - Put the declarations at the start of the block (cherry picked from commit 944a3329b05510d55c69c2ef455136e2fc02de29)

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/ffba51100ff61792fefbae11ca38ac1987a818dd
• https://git.kernel.org/stable/c/79f52655567a6471ff3d0d6325ede91bb14461f4
• https://git.kernel.org/stable/c/fbbe32618e97eff81577a01eb7d9adcd64a216d7