[v0.20] Nil CDI manager can cause errors

[tonistiigi]

When CDI is disabled in the config, it is initialized to nil value. Looks like while some code paths like ListDevices handle nil value, some like InjectDevices do not.

[crazy-max]

Looks like while some code paths like ListDevices handle nil value, some like InjectDevices do not.

InjectDevices is only called through

buildkit/executor/oci/spec_linux.go

Line 155 in 6702365

func generateCDIOpts(manager *cdidevices.Manager, devs []*pb.CDIDevice) ([]oci.SpecOpts, error) {

But we check if cdiManager is not nil in such case:

buildkit/executor/oci/spec.go

Lines 133 to 139 in 6702365

	if cdiManager != nil {
	if cdiOpts, err := generateCDIOpts(cdiManager, meta.CDIDevices); err == nil {
	opts = append(opts, cdiOpts...)
	} else {
	return nil, nil, err
	}
	}

The only case I see where it could panic is

buildkit/solver/llbsolver/ops/exec.go

Line 203 in 6702365

setup, ok := e.w.CDIManager().OnDemandInstaller(d.Name)