Fix kmsg watcher restart and shutdown issues#1311
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kubernetes-prow[bot] merged 3 commits intoJul 11, 2026
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If the restarted parser's channel closes again right away (reads keep failing on the reopened /dev/kmsg), the watcher restarts in a tight loop with no delay, spinning a CPU core and flooding the logs (measured 37k restarts in 200ms). Delay the first attempt when the previous restart was less than retryDelay ago.
The log monitor stops draining logCh before calling watcher.Stop(), so with a full channel (e.g. a kmsg burst at shutdown) watchLoop blocked on the send forever, never called tomb.Done(), and Stop() hung. Select on tomb.Stopping() alongside the send.
…nterrupts a restart The restart path closes the failed parser before retrying. If stopping is signaled during the retry wait, watchLoop's deferred cleanup closed the same parser again, logging a spurious 'file already closed' error at shutdown. Clear the reference after closing and nil-check the defer.
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Review of the recent kmsg restart changes (#1192, #1245, #1259) surfaced three issues, one commit each:
logChfull and the consumer already stopping,watchLoopblocked on a plain send andStop()hung.Stop()interrupts a restart attempt, the deferred cleanup closed the already-closed old parser, logging a spurious error.Each fix comes with a regression test; the package passes
go test -race.