Linux kernel amdkfd (KFD compute driver, /dev/kfd) (amdkfd): MULTI-TENANT ISOLATION: An out-of-bounds access

Impact

MULTI-TENANT ISOLATION: An out-of-bounds access in the amdkfd (KFD compute driver, /dev/kfd) - a length, index or size supplied through the driver interface is used without a proper bound check. Depending on the path this reads kernel memory back to the caller (leaking whatever happens to sit past the buffer, including other tenants' data still resident in the slab) or writes past the allocation, which is a kernel heap-corruption and privilege-escalation primitive. Upstream fix: amdkfd: use calloc instead of kzalloc to avoid integer overflow

Who can reach it

Local. Reachable by any process or container with /dev/kfd and /dev/dri/renderD* mapped in - which is every ROCm workload, including an unprivileged tenant pod. Not reachable over the network and not reachable from a container that has no GPU device node mapped in.

What to do

Kernel-side fix: this lands in mainline Linux and flows into distro kernels (RHEL/Rocky, Ubuntu HWE, SLES) and into AMD's out-of-tree DKMS amdgpu package shipped with ROCm. Patch the kernel or the DKMS module, then **reload the amdgpu module or reboot the node** - you cannot fix a running driver in place. Reloading amdgpu requires no process holding /dev/kfd or a render node, so in practice this is a cordon + drain + reboot per node. Plan it as a rolling maintenance across the fleet; there is no VBIOS flash, no SBIOS/AGESA step and no firmware update involved. Nodes running the ROCm DKMS stack often lag mainline by a release or two, so confirm the fix is actually present in the AMD driver version you deploy rather than assuming a new distro kernel covers it. Until the reboot window, the only real mitigation is to stop handing the render node to untrusted workloads - the device plugin has to be mapping /dev/dri/renderD* and /dev/kfd into the container for a tenant to reach this at all.

References