LoadIngress reads the ingress info and its state from two separate Redis
keys non-atomically, while DeleteIngress removes both keys in a single
transaction. If the delete lands between the two reads, LoadIngress
returns an IngressInfo with a nil State and no error, and
UpdateIngressState panics dereferencing info.State.Status — taking down
the whole server with every room it hosts.
The race fires in practice when an ingress session is being torn down by
DeleteIngress and the ingress service reports the session state change
concurrently: with short-lived per-room WHIP ingresses this crashed
production servers within minutes (observed on v1.13.5 and v1.13.6,
SIGSEGV at ioservice_ingress.go:82, addr=0x8).
Guard the nil State by treating it as an empty state, matching how the
store's UpdateIngressState already tolerates a missing state key.
Nicolas Buszczak
3a7228fa74