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make the server's shutdown flag atomic - #1278
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Server::stop() writes shutting_down_ on the thread that calls app.stop(), while the io thread reads it in do_accept() and its accept handler. As a plain bool nothing orders those accesses, which ThreadSanitizer reports as a data race whenever an app is stopped from another thread. Fixes CrowCpp#1277 Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
gittiver
approved these changes
Oct 15, 2026
gittiver
approved these changes
Oct 15, 2026
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Server::stop()writesshutting_down_on the thread that callsapp.stop(). The io thread reads it indo_accept(), which the accept handler calls again after every accepted connection, and in that handler's error path. As a plainbool, nothing orders those accesses, so stopping an app from another thread (the usual way to stop one started withrun_async()) is a data race that ThreadSanitizer reports. This makes the flagstd::atomic<bool>.<atomic>is already included, and the write and both reads are unchanged.Fixes #1277
Verification:
run_async(), make one request, stop from the main thread, repeated) was built with-fsanitize=thread. Over 10 runs of 50 cycles, master reports the race in 9 runs; with this change all 10 exit 0 with no reports.crow_testandtemplate_testpass.No test added: the race only fails under ThreadSanitizer, and the CI sanitizer job runs ASan and UBSan, so a test here would pass either way. If you'd like a TSan job in CI, I can open that separately.
This change and its description were prepared with Claude Code.