Possible regression in latest runsc release: kaniko writes fail with "operation not supported" on /kaniko/*

Hi gVisor team, We are seeing a regression when using recent `runsc` binaries from `release/latest` with kaniko-based image builds on Kubernetes. ## Impact Our builder pods fail consistently during image build preparation with filesystem write errors under `/kaniko`. Example errors: - `error resolving source context: unpacking tar from build context: mkdir /kaniko/buildcontext/: operation not supported` - `error resolving dockerfile path: copying dockerfile: creating file: open /kaniko/Dockerfile: operation not supported` ## What changed We were downloading runsc from: - `https://storage.googleapis.com/gvisor/releases/release/latest/${ARCH}` After rollback/pin to an older release, builds recover: - working release: `release-20260504.0` - URL form used by our bootstrap: `https://storage.googleapis.com/gvisor/releases/release/20260504.0/${ARCH}` This rollback was the only meaningful change and resolved the issue end-to-end. ## Environment - Kubernetes: EKS 1.33 - Runtime class: `gvisor` (containerd runsc runtime) - Workload: kaniko executor in k8s Job - Node bootstrap installed runsc + `containerd-shim-runsc-v1` from gVisor release bucket ## Ask Could you please confirm whether there was a recent behavioral change around overlay/write semantics that might affect writing to the filesystem in a gVsior runtime container? If this is expected, any recommended runtime flags or config guidance to preserve compatibility would be very helpful. Happy to provide more diagnostics if you want specific logs or `runsc`/containerd config details. Thanks!