Potential data race in Poco::SharedPtr reported by TSAN

[jbulow]

I see the following report from clang's thread sanitizer:

WARNING: ThreadSanitizer: data race (pid=18496)
Atomic write of size 4 at 0x7b040001c1f0 by thread T3 (mutexes: write M35319715098537976, write M42356589516556368, write M224752683662668696, write M1065241059421923688):
#0 __tsan_atomic32_fetch_sub /home/jonasbu/llvm/projects/compiler-rt/lib/tsan/rtl/tsan_interface_atomic.cc:643 (nsp_servers+0x4aacec)
#1 Poco::AtomicCounter::operator--() /artifacts/external/poco/deliverables/interface/Poco/AtomicCounter.h:314:9 (libcsc.so+0x203172)
#2 Poco::ReferenceCounter::release() /artifacts/external/poco/deliverables/interface/Poco/SharedPtr.h:47:10 (libcsc.so+0x203088)
#3 Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable >::release() /artifacts/external/poco/source/poco-1.7.9-all/Foundation/include/Poco/SharedPtr.h:393:22 (libPocoFoundationd.so.49+0x2e1e80)
#4 Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable >::~SharedPtr() /artifacts/external/poco/source/poco-1.7.9-all/Foundation/include/Poco/SharedPtr.h:148:4 (libPocoFoundationd.so.49+0x2e1ba8)
#5 Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable >::assign(Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable > const&) /artifacts/external/poco/source/poco-1.7.9-all/Foundation/include/Poco/SharedPtr.h:172:3 (libPocoFoundationd.so.49+0x2e200a)
#6 Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable >::operator=(Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable > const&) /artifacts/external/poco/source/poco-1.7.9-all/Foundation/include/Poco/SharedPtr.h:194:10 (libPocoFoundationd.so.49+0x2e1458)
#7 Poco::ThreadImpl::startImpl(Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable >) /artifacts/external/poco/source/poco-1.7.9-all/Foundation/src/Thread_POSIX.cpp:205:26 (libPocoFoundationd.so.49+0x2de7be)
#8 Poco::Thread::start(Poco::Runnable&) /artifacts/external/poco/source/poco-1.7.9-all/Foundation/src/Thread.cpp:130:2 (libPocoFoundationd.so.49+0x2e03c7)

...

Previous write of size 8 at 0x7b040001c1f0 by thread T156:
#0 operator new(unsigned long) /home/jonasbu/llvm/projects/compiler-rt/lib/tsan/rtl/tsan_new_delete.cc:57 (nsp_servers+0x4d1e53)
#1 Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable >::SharedPtr(Poco::Runnable*) /artifacts/external/poco/source/poco-1.7.9-all/Foundation/include/Poco/SharedPtr.h:124:13 (libPocoFoundationd.so.49+0x2e1a8a)
#2 Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable >::assign(Poco::Runnable*) /artifacts/external/poco/source/poco-1.7.9-all/Foundation/include/Poco/SharedPtr.h:160:14 (libPocoFoundationd.so.49+0x2e233f)
#3 Poco::SharedPtr<Poco::Runnable, Poco::ReferenceCounter, Poco::ReleasePolicyPoco::Runnable >::operator=(Poco::Runnable*) /artifacts/external/poco/source/poco-1.7.9-all/Foundation/include/Poco/SharedPtr.h:189:10 (libPocoFoundationd.so.49+0x2e14c8)
#4 Poco::ThreadImpl::runnableEntry(void*) /artifacts/external/poco/source/poco-1.7.9-all/Foundation/src/Thread_POSIX.cpp:364:25 (libPocoFoundationd.so.49+0x2df014)

Is it a real issue or a false positive? Using shared pointers from std or boost does not have this problem.

[github-actions]

This issue is stale because it has been open for 365 days with no activity.

[aleks-f]

TSAN CI passes cleanly, most likely fixed in 1.12.0
#3617