hubble: Fix Race in Hubble Consumer #15967
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nathanjsweet
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I was looking through the hubble code today to see who the BPF Perf map got transmuted into the bubble perf ring buffer, to see if there was a possibility of a direct read situation (seems like it's not possible). In the course of doing that though I ran into this, which I think is a legitimate bug. |
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gandro
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michi-covalent
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When the hubble event consumer channel is full there is a possible race condition. The code was structured such that the consumer could end up losing the count of lost events, because it was updating the count without a lock. Additionally, it could reach a condition wherein it would reset the count and send a notification of recovery more than once. Finally, there was a log message for dropped events, but it was "debug" level event rather than the warning that it should be. Signed-off-by: Nate Sweet <nathanjsweet@pm.me>
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glibsm
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nathanjsweet
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test-me-please |
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Please triage the 5 failing checks and if they're all truly unrelated, briefly describe why we should be able to ignore them. |
joestringer
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All test failures were either network or DNS failures, and in one weird case a success that was supposed to be a failure. The likelihood that any of these failures was caused by this PR is as close to nil as I can imagine. |
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When the hubble event consumer channel is full there is
a possible race condition. The code was structured such that
the consumer could end up losing the count of lost events, because
it was updating the count without a lock. Additionally, it could
reach a condition wherein it would reset the count and send a
notification of recovery more than once.
Finally, there was a log message for dropped events, but it was
"debug" level event rather than the warning that it should be.
Signed-off-by: Nate Sweet nathanjsweet@pm.me