maskit commented on issue #7562: URL: https://github.com/apache/trafficserver/issues/7562#issuecomment-786355180
The crash happens if a producer is throttled (flow controlled) and background fill starts. Workaround is to disable flow control (`proxy.config.http.flow_control.enabled`). Here is the detail: `consumer_handler` calls `HttpSM::tunnel_handler_ua` here https://github.com/apache/trafficserver/blob/e24c79a4a530dc9b12880503e8c047e5610c3224/proxy/http/HttpTunnel.cc#L1317-L1330 And if background fill starts in `HttpSM::tunnel_handler_ua`, a consumer for client is closed here. https://github.com/apache/trafficserver/blob/e24c79a4a530dc9b12880503e8c047e5610c3224/proxy/http/HttpSM.cc#L3326-L3329 So the consumer `c` is no longer available at this point. However, this block somehow calls `consumer_reenable` for the consumer that has just been closed, despite the comment. https://github.com/apache/trafficserver/blob/e24c79a4a530dc9b12880503e8c047e5610c3224/proxy/http/HttpTunnel.cc#L1367-L1379 `consumer_reenable` uses the consumer here and ATS crashes, because `write_vio` is null. https://github.com/apache/trafficserver/blob/e24c79a4a530dc9b12880503e8c047e5610c3224/proxy/http/HttpTunnel.cc#L1272-L1280 The reenabling above won't happen if flow control is disabled, because throttling happens only if flow control is enabled. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
