Author: labath Date: Fri Apr 15 05:49:07 2016 New Revision: 266423 URL: http://llvm.org/viewvc/llvm-project?rev=266423&view=rev Log: Work around a linux libc bug causing a crash in TaskPool
Summary: Doing a pthread_detach while the thread is exiting can cause crashes or other mischief, so we make sure the thread stays around long enough. The performance impact of the added synchronization should be minimal, as the parent thread is already holding a mutex, so I am just making sure it holds it for a little while longer. It's possible the new thread will block on this mutex immediately after startup, but it should be unblocked really quickly and some blocking is unavoidable if we actually want to have this synchronization. Reviewers: tberghammer Subscribers: lldb-commits Differential Revision: http://reviews.llvm.org/D19153 Modified: lldb/trunk/source/Utility/TaskPool.cpp Modified: lldb/trunk/source/Utility/TaskPool.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Utility/TaskPool.cpp?rev=266423&r1=266422&r2=266423&view=diff ============================================================================== --- lldb/trunk/source/Utility/TaskPool.cpp (original) +++ lldb/trunk/source/Utility/TaskPool.cpp Fri Apr 15 05:49:07 2016 @@ -61,8 +61,9 @@ TaskPoolImpl::AddTask(std::function<void if (m_thread_count < max_threads) { m_thread_count++; - lock.unlock(); - + // Note that this detach call needs to happen with the m_tasks_mutex held. This prevents the thread + // from exiting prematurely and triggering a linux libc bug + // (https://sourceware.org/bugzilla/show_bug.cgi?id=19951). std::thread (Worker, this).detach(); } } _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
