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From: "boris at kolpackov dot net" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug sanitizer/101978] thread sanitizer false positive when condition variable Date: Mon, 18 Jul 2022 11:35:35 +0000 [thread overview] Message-ID: <bug-101978-4-4WNCc9LPPp@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-101978-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101978 Boris Kolpackov <boris at kolpackov dot net> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |boris at kolpackov dot net --- Comment #4 from Boris Kolpackov <boris at kolpackov dot net> --- Reproduces with GCC 11.3.0 from Debian. There is speculation on StackOverflow that links to this bug that this is somehow causes by holding the mutex while calling notify_all(). But in our case we get this bogus report without holding the mutex when calling notify_all(). Here is what the relevant parts in our code look like: { unique_lock l (state_->mutex); state_->finished = true; } state_->condv.notify_all (); And: unique_lock l (state_->mutex); if (!state_->finished && !state_->condv.wait_for (l, tm, [state_] {return state_->finished;})) return nullopt; Also, in our case we get two variants of this warning: as originally reported and the second where the mutex is supposedly already destroyed (shown below). Replacing wait_for() with wait() makes both disappear. WARNING: ThreadSanitizer: double lock of a mutex (pid=1881) #0 pthread_mutex_lock ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:4240 (libtsan.so.0+0x4f30a) #1 __gthread_mutex_lock /usr/include/x86_64-linux-gnu/c++/11/bits/gthr-default.h:749 (libbuild2-0.15.0-a.0.ecfa0f59dab6.so+0x624ff5) #2 std::mutex::lock() /usr/include/c++/11/bits/std_mutex.h:100 (libbuild2-0.15.0-a.0.ecfa0f59dab6.so+0x625146) #3 std::unique_lock<std::mutex>::lock() /usr/include/c++/11/bits/unique_lock.h:139 (libbuild2-0.15.0-a.0.ecfa0f59dab6.so+0x62c701) #4 std::unique_lock<std::mutex>::unique_lock(std::mutex&) /usr/include/c++/11/bits/unique_lock.h:69 (libbuild2-0.15.0-a.0.ecfa0f59dab6.so+0x62c64c) #5 operator() /tmp/bootstrap/build2-toolchain-0.15-a.0/libbutl-0.15.0-a.0.20220714150118.f07a6606e44d/libbutl/builtin.ixx:56 (libbutl-0.15.0-a.0.f07a6606e44d.so+0x24d443) ... Location is heap block of size 104 at 0x7b1c00017370 allocated by thread T9: #0 operator new(unsigned long) ../../../../src/libsanitizer/tsan/tsan_new_delete.cpp:64 (libtsan.so.0+0x8857c) #1 async_impl /tmp/bootstrap/build2-toolchain-0.15-a.0/libbutl-0.15.0-a.0.20220714150118.f07a6606e44d/libbutl/builtin.cxx:2191 (libbutl-0.15.0-a.0.f07a6606e44d.so+0x248ee8) #2 async_impl<butl::echo> /tmp/bootstrap/build2-toolchain-0.15-a.0/libbutl-0.15.0-a.0.20220714150118.f07a6606e44d/libbutl/builtin.cxx:2205 (libbutl-0.15.0-a.0.f07a6606e44d.so+0x24db72) #3 run_pipe /tmp/bootstrap/build2-toolchain-0.15-a.0/build2-0.15.0-a.0.20220717074539.ecfa0f59dab6/libbuild2/script/run.cxx:2160 (libbuild2-0.15.0-a.0.ecfa0f59dab6.so+0x82a1ec) #4 run_expr /tmp/bootstrap/build2-toolchain-0.15-a.0/build2-0.15.0-a.0.20220717074539.ecfa0f59dab6/libbuild2/script/run.cxx:2492 (libbuild2-0.15.0-a.0.ecfa0f59dab6.so+0x82c409) ... Mutex M810501818139374456 is already destroyed.
next prev parent reply other threads:[~2022-07-18 11:35 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-19 14:31 [Bug sanitizer/101978] New: thread sanitizer false positive when smart pointers ispavlick at gmail dot com 2021-08-19 16:59 ` [Bug sanitizer/101978] " ispavlick at gmail dot com 2021-08-20 7:53 ` [Bug sanitizer/101978] thread sanitizer false positive when condition variable marxin at gcc dot gnu.org 2022-02-20 6:04 ` danregister at poczta dot fm 2022-07-18 11:35 ` boris at kolpackov dot net [this message] 2022-07-28 15:36 ` lewis at sophists dot com 2022-09-23 14:52 ` jakob.weisblat at zoom dot us 2022-09-23 16:44 ` pinskia at gcc dot gnu.org 2022-09-23 16:47 ` jakob.weisblat at zoom dot us 2022-09-23 17:19 ` redi at gcc dot gnu.org 2022-09-23 18:30 ` redi at gcc dot gnu.org
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