topologySpreadConstriants with empty labelSelector makes karpenter crash

[olemarkus]

Version

Karpenter: v0.5.3

Kubernetes: v1.22.4

Actual Behavior

Karpenter crash with an npr if a Pod has a topologySpreadConstraint with empty labelSelector. Empty labelSelectors doesn't make much sense, but still shouldn't crash karpenter.

Resource Specs and Logs

Just ignoring the spread constraint is probably fine if the labelSelector is empty.

2021-12-19T07:40:14.064Z        INFO    controller.provisioning Batched 2 pods in 1.000147818s  {"commit": "5047f3c", "provisioner": "karpenter-nodes"}
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x19daf66]

goroutine 10410 [running]:
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.TopologyListOptions({0xc000bdb0b0, 0xb}, 0xc00410e820)
        github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:144 +0x66
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Topology).countMatchingPods(0xc00376cf10, {0x27965b8, 0xc001184db0}, 0xc00410e820)
        github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:122 +0x85
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Topology).computeZonalTopology(0xc00410e870, {0x27965b8, 0xc001184db0}, {0xc0024acea0, 0x0, 0x0}, 0x0)
        github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:114 +0x7e
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Topology).computeCurrentTopology(0x0, {0x27965b8, 0xc001184db0}, 0xc000c5dda0, 0xc00410e820)
        github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:82 +0x93
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Topology).Inject(0xc00118e2d8, {0x27965b8, 0xc001184db0}, 0xc000c5dda0, {0xc004902790, 0xc000c5dd68, 0x1})
        github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:45 +0xbf
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Scheduler).Solve(0xc003769740, {0x27965b8, 0xc001184db0}, 0xc00118e1c0, {0xc004902790, 0x2, 0x2})
        github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/scheduler.go:73 +0x1c8
github.com/aws/karpenter/pkg/controllers/provisioning.(*Provisioner).provision(0xc0003cc540, {0x27965b8, 0xc001184db0})
        github.com/aws/karpenter/pkg/controllers/provisioning/provisioner.go:116 +0x208
github.com/aws/karpenter/pkg/controllers/provisioning.NewProvisioner.func1()
        github.com/aws/karpenter/pkg/controllers/provisioning/provisioner.go:65 +0x73
created by github.com/aws/karpenter/pkg/controllers/provisioning.NewProvisioner
        github.com/aws/karpenter/pkg/controllers/provisioning/provisioner.go:63 +0x3a5

[jalawala]

I also saw crash with below configs
nodeSelector:
kubernetes.io/arch: amd64
topologySpreadConstraints:
- maxSkew: 5
topologyKey: "topology.kubernetes.io/zone"
whenUnsatisfiable: ScheduleAnyway

2021-12-21T11:47:25.368Z INFO controller.provisioning Batched 18 pods in 1.506678526s {"commit": "5047f3c", "provisioner": "default"}
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x19daf66]

goroutine 133726 [running]:
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.TopologyListOptions({0xc006bbf4e0, 0x7}, 0xc0046b1630)
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:144 +0x66
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Topology).countMatchingPods(0xc003d2ea80, {0x27965b8, 0xc0046af710}, 0xc0046b1630)
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:122 +0x85
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Topology).computeZonalTopology(0x0, {0x27965b8, 0xc0046af710}, {0xc0044ff6c0, 0x0, 0x0}, 0x0)
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:114 +0x7e
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Topology).computeCurrentTopology(0x0, {0x27965b8, 0xc0046af710}, 0xc004737da0, 0xc0046b1630)
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:82 +0x93
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Topology).Inject(0xc003c070d8, {0x27965b8, 0xc0046af710}, 0xc004737da0, {0xc0046b5800, 0xc004737d68, 0xc0045e6320})
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/topology.go:45 +0xbf
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling.(*Scheduler).Solve(0xc0001830e0, {0x27965b8, 0xc0046af710}, 0xc003c06fc0, {0xc0046b5800, 0x12, 0x20})
github.com/aws/karpenter/pkg/controllers/provisioning/scheduling/scheduler.go:73 +0x1c8
github.com/aws/karpenter/pkg/controllers/provisioning.(*Provisioner).provision(0xc002f60cb0, {0x27965b8, 0xc0046af710})
github.com/aws/karpenter/pkg/controllers/provisioning/provisioner.go:116 +0x208
github.com/aws/karpenter/pkg/controllers/provisioning.NewProvisioner.func1()
github.com/aws/karpenter/pkg/controllers/provisioning/provisioner.go:65 +0x73
created by github.com/aws/karpenter/pkg/controllers/provisioning.NewProvisioner
github.com/aws/karpenter/pkg/controllers/provisioning/provisioner.go:63 +0x3a5