ThreadSanitizer Usage?

[xanderdunn]

I have a project that's using tokio and when I run it with the thread sanitizer I see a ton of warnings. I'm not sure if they're potentially valid or if they're false positives. A search for tsan in the tokio repo shows that the project used to test using the thread sanitizer in CI around 2018. I see it was temporarily disabled in 2018 due to too many false positives, but haven't seen anything after that. Is the thread sanitizer been abandoned due to too many false positives? Is this not going to be a useful tool for a project written using tokio?

[Darksonn]

I have no idea what the situation for false positives is today. We enabled ASAN testing not too long ago, and if we can get TSAN testing to work, I would definitely be open to that.

[jtbandes]

I'm interested in this too! I attempted to use TSan with a library that depends on tokio (foxglove/foxglove-sdk#282) and I started seeing some "races" that had nothing to do with my code, for example between ScheduledIo::set_readiness and RegistrationSet::allocate:

3: WARNING: ThreadSanitizer: data race (pid=5875)
3:   Atomic read of size 8 at 0x724000000490 by thread T1:
3:     #0 tokio::runtime::io::scheduled_io::ScheduledIo::set_readiness::hd03c2f604d39da38 <null> (tests+0x26b1d3) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #1 tokio::runtime::io::driver::Driver::turn::hd8a52ba52dfdd094 (.llvm.18164847348764476444) <null> (tests+0x29b652) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #2 tokio::runtime::io::driver::Driver::park::h5277cbb981b2c7af <null> (tests+0x29abc7) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #3 tokio::runtime::driver::IoStack::park::h98cc04894bb58df8 <null> (tests+0x261cb0) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #4 tokio::runtime::time::Driver::park_internal::heed23f95697eebe0 (.llvm.6904112984268731359) <null> (tests+0x2bbf42) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #5 tokio::runtime::time::Driver::park_internal::heed23f95697eebe0 (.llvm.6904112984268731359) <null> (tests+0x2bbf42) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #6 tokio::runtime::driver::Driver::park::hbe1958d48465f065 <null> (tests+0x261878) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #7 tokio::runtime::scheduler::multi_thread::park::Parker::park::h356cc6abbf338bed <null> (tests+0x26f909) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #8 tokio::runtime::scheduler::multi_thread::park::Parker::park::h356cc6abbf338bed <null> (tests+0x26f909) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #9 tokio::runtime::scheduler::multi_thread::worker::Context::park_timeout::hac02736e28120ec5 tokio.2feaed4e719b079e-cgu.15 (tests+0x2c1888) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #10 tokio::runtime::scheduler::multi_thread::worker::Context::run::h39bfa6b25df7651d <null> (tests+0x2c0b0c) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #11 tokio::runtime::context::runtime::enter_runtime::h073e3b7caf4e7ad7 <null> (tests+0x2b942c) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #12 tokio::runtime::scheduler::multi_thread::worker::run::h52a352426c455b87 <null> (tests+0x2bfe18) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #13 _$LT$tokio..runtime..blocking..task..BlockingTask$LT$T$GT$$u20$as$u20$core..future..future..Future$GT$::poll::h0d7db37df4813521 <null> (tests+0x277d38) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #14 tokio::runtime::task::core::Core$LT$T$C$S$GT$::poll::h6c9c8b7041eb839c <null> (tests+0x283620) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #15 std::panicking::try::do_call::hc2d3f244adcc218a tokio.2feaed4e719b079e-cgu.07 (tests+0x28ee43) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #16 __rust_try.llvm.5039682606586733369 <null> (tests+0x292435) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #17 tokio::runtime::task::harness::Harness$LT$T$C$S$GT$::poll::h1536782db7b6da0c <null> (tests+0x29054b) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #18 tokio::runtime::task::raw::poll::h7966616cc9ef021d (.llvm.11477606333223759851) <null> (tests+0x284d19) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #19 tokio::runtime::task::raw::RawTask::poll::h7c99c9d967574d53 <null> (tests+0x284add) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #20 tokio::runtime::task::UnownedTask$LT$S$GT$::run::h7d089ee75952be72 <null> (tests+0x2b250b) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #21 std::sys::backtrace::__rust_begin_short_backtrace::hd25300b199868c7a <null> (tests+0x293409) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #22 std::panicking::try::do_call::haf2ca189ad4f2132 (.llvm.6374102638783195263) <null> (tests+0x286fed) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #23 __rust_try.llvm.6374102638783195263 <null> (tests+0x28e6e5) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #24 core::ops::function::FnOnce::call_once$u7b$$u7b$vtable.shim$u7d$$u7d$::h4a41540dc9fc6a1e tokio.2feaed4e719b079e-cgu.06 (tests+0x287bd5) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #25 _$LT$alloc..boxed..Box$LT$F$C$A$GT$$u20$as$u20$core..ops..function..FnOnce$LT$Args$GT$$GT$::call_once::h5d3c9f55fd46a084 <null> (tests+0x3fa691) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #26 std::sys::pal::unix::thread::Thread::new::thread_start::he36c0e0a3faff8bc std.511a7f6bcb35bf27-cgu.08 (tests+0x437ff3) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3: 
3:   Previous write of size 8 at 0x724000000490 by main thread (mutexes: write M0):
3:     #0 __tsan_memcpy <null> (tests+0xb661f) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #1 tokio::runtime::io::registration_set::RegistrationSet::allocate::h35cfc759f205704a <null> (tests+0x29f03a) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #2 tokio::runtime::io::driver::Handle::add_source::hda26c19fb7a890f8 <null> (tests+0x29d458) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #3 tokio::runtime::io::registration::Registration::new_with_interest_and_handle::hd794af2ca29400d2 <null> (tests+0x2646c7) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #4 tokio::io::poll_evented::PollEvented$LT$E$GT$::new_with_interest::hcc1f082c645c13b4 <null> (tests+0x2ac830) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #5 tokio::net::tcp::listener::TcpListener::bind_addr::h73e92b72af1f8ceb <null> (tests+0x295ed2) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #6 tokio::runtime::handle::Handle::block_on::h642229b8b3c87eb9 <null> (tests+0x20af92) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #7 foxglove::websocket_server::WebSocketServer::start_blocking::haeef885a3c634910 <null> (tests+0x1d44a2) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #8 foxglove_server_start <null> (tests+0x1c8124) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #9 foxglove::WebSocketServer::WebSocketServer(foxglove::WebSocketServerOptions) /home/runner/work/foxglove-sdk/foxglove-sdk/cpp/foxglove/src/server.cpp:30:15 (tests+0x1c5cf3) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #10 CATCH2_INTERNAL_TEST_4() /home/runner/work/foxglove-sdk/foxglove-sdk/cpp/foxglove/tests/test_server.cpp:64:29 (tests+0x13b94f) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #11 Catch::TestCaseHandle::invoke() const /home/runner/work/foxglove-sdk/foxglove-sdk/cpp/build-sanitize-thread/_deps/catch2-build/src/src/catch2/../catch2/catch_test_case_info.hpp:124:24 (tests+0x62352e) (BuildId: ca4d41c4554d22bc149eb76ece80f3c893e10caa)
3:     #12 Catch::RunContext::invokeActiveTestCase() /home/runner/work/foxglove-sdk/foxglove-sdk/cpp/build-sanitize-thread/_deps/catch2-build/src/src/catch2/internal/catch_run_context.cpp:580:27 (tests+0x62352e)
3:     #13 Catch::RunContext::runCurrentTest() /home/runner/work/foxglove-sdk/foxglove-sdk/cpp/build-sanitize-thread/_deps/catch2-build/src/src/catch2/internal/catch_run_context.cpp:543:17 (tests+0x62352e)

[Darksonn]

Things from 2022 are probably not relevant anymore. But you can open a new issue.