some 503s being caused by activator panic & container restart

[dprotaso]

What version of Knative?

1.2

Crash

panic: interface conversion: interface {} is cache.DeletedFinalStateUnknown, not *v1.Revision

goroutine 91 [running]:
k8s.io/apimachinery/pkg/util/runtime.HandleCrash({0x0, 0x0, 0x1})
	k8s.io/[email protected]/pkg/util/runtime/runtime.go:55 +0xd8
panic({0x18a2d20, 0xc0015acea0})
	runtime/panic.go:1038 +0x215
knative.dev/serving/pkg/activator/net.(*Throttler).revisionDeleted(0x4067e0, {0x192cf80, 0xc00093c820})
	knative.dev/serving/pkg/activator/net/throttler.go:573 +0x2a5
k8s.io/client-go/tools/cache.ResourceEventHandlerFuncs.OnDelete(...)
	k8s.io/[email protected]/tools/cache/controller.go:245
k8s.io/client-go/tools/cache.(*processorListener).run.func1()
	k8s.io/[email protected]/tools/cache/shared_informer.go:779 +0xdf
k8s.io/apimachinery/pkg/util/wait.BackoffUntil.func1(0x7f90530d6d98)
	k8s.io/[email protected]/pkg/util/wait/wait.go:155 +0x67
k8s.io/apimachinery/pkg/util/wait.BackoffUntil(0xc000073738, {0x1d17460, 0xc000b1d350}, 0x1, 0xc000b62240)
	k8s.io/[email protected]/pkg/util/wait/wait.go:156 +0xb6
k8s.io/apimachinery/pkg/util/wait.JitterUntil(0xc000574540, 0x3b9aca00, 0x0, 0x17, 0xc0000737b0)
	k8s.io/[email protected]/pkg/util/wait/wait.go:133 +0x89
k8s.io/apimachinery/pkg/util/wait.Until(...)
	k8s.io/[email protected]/pkg/util/wait/wait.go:90
k8s.io/client-go/tools/cache.(*processorListener).run(0xc000b1a700)
	k8s.io/[email protected]/tools/cache/shared_informer.go:771 +0x6b
k8s.io/apimachinery/pkg/util/wait.(*Group).Start.func1()
	k8s.io/[email protected]/pkg/util/wait/wait.go:73 +0x5a
created by k8s.io/apimachinery/pkg/util/wait.(*Group).Start
	k8s.io/[email protected]/pkg/util/wait/wait.go:71 +0x88

/assign @dprotaso

[dprotaso]

https://pkg.go.dev/k8s.io/client-go/tools/cache#DeletedFinalStateUnknown

DeletedFinalStateUnknown is placed into a DeltaFIFO in the case where an object was deleted but the watch deletion event was missed while disconnected from apiserver. In this case we don't know the final "resting" state of the object, so there's a chance the included Obj is stale.