Database/Kernel, userspace & hypervisor
Intel CPU (Downfall / GDS): Downfall: Gather Data Sampling leaks AVX gather-instruction data across SMT siblings
Impact
Downfall: Gather Data Sampling leaks AVX gather-instruction data across SMT siblings, containers and VMs - directly breaks multi-tenant isolation
Who can reach it
Any tenant process in a container; tenant VM guest
What to do
Microcode update + reboot, standing perf cost (reported up to ~50% on gather-heavy vector code). Alternative is disabling AVX gather, which is worse for AI workloads. On shared-GPU nodes with co-tenanted CPUs this is a must-fix
Fleet impact
How widespread
very common - Skylake through Tiger Lake era Xeons, still the host CPU under a large installed base of GPU nodes
Cost to remediate
microcode+reboot - microcode is loaded at boot, so every node drains and reboots; the mitigation carries a measurable AVX2/AVX-512 gather slowdown, i.e. a permanent throughput tax on the fleet
Why it hits the whole fleet
Cross-tenant data leakage from stale vector registers on shared hardware - exactly the isolation property a multi-tenant GPU cloud sells - so it forces a fleet-wide reboot campaign regardless of workload.
References
This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.