limit_zone and nginx worker crashing

[Matthieu Tourne]

Hi,

I've noticed an issue when limit_zone (and probably limit_req) is used.
If an nginx worker crashes, the cleanup functions for that request will not
get called and the number of connections will not be decremented as it
should be in ngx_http_limit_zone_cleanup().

Since it's a shared memory segment when a new worker is started, the number
of connection is still at the same value.
So if a worker crashes multiple times, we might end up always returning '503
Service Temporary Unavailable'.

I'm not sure there would be a way to call the cleanup functions if a worker
has crashed, but maybe the rbtree for limit_zone should be re-initialized on
a respawn ?

Thanks!

Matthieu.
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