Fix buffer overflow in SDMA queue checkpoint/restore on GFX11

Summary

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: Fix buffer overflow in SDMA queue checkpoint/restore on GFX11 The v11 MQD manager incorrectly assigned the CP-compute variants of checkpoint_mqd/restore_mqd for KFD_MQD_TYPE_SDMA queues. These functions use sizeof(struct v11_compute_mqd) (2048 bytes) instead of sizeof(struct v11_sdma_mqd) (512 bytes), causing a 1536-byte overflow. During CRIU checkpoint of an SDMA queue on Navi3x: - checkpoint_mqd() reads 2048 bytes from a 512-byte SDMA MQD buffer, leaking 1536 bytes of adjacent GTT memory to userspace During CRIU restore: - restore_mqd() writes 2048 bytes into a 512-byte SDMA MQD buffer, corrupting 1536 bytes of adjacent GTT memory (often the ring buffer or neighboring MQDs) This is a copy-paste regression unique to v11. All other ASIC backends (cik, vi, v9, v10, v12) correctly use the SDMA-specific variants. Add checkpoint_mqd_sdma() and restore_mqd_sdma() functions that properly handle the smaller v11_sdma_mqd structure, matching the pattern used in other MQD managers. (cherry picked from commit 6fa41db7ffdec97d62433adf03b7b9b759af8c2c) A flaw was found in the Linux kernel's AMD KFD (Kernel Fusion Driver) component. This buffer overflow vulnerability occurs due to incorrect memory buffer handling during CRIU (Checkpoint/Restore in User-space) operations on SDMA (System Direct Memory Access) queues. A local attacker can exploit this flaw during CRIU restore operations, which can lead to memory corruption in adjacent kernel memory, potentially impacting system stability or leading to further compromise. Additionally, during CRIU checkpoint operations, this vulnerability can result in information disclosure of adjacent kernel memory to userspace. Red Hat severity: Important — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-131. No fixing RHSA erratum has published yet; monitor the Red Hat CVE page and patch when it ships.