labath created this revision.
labath added a reviewer: tberghammer.
labath added a subscriber: lldb-commits.
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.
http://reviews.llvm.org/D19153
Files:
source/Utility/TaskPool.cpp
Index: source/Utility/TaskPool.cpp
===================================================================
--- source/Utility/TaskPool.cpp
+++ source/Utility/TaskPool.cpp
@@ -61,8 +61,9 @@
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();
}
}
Index: source/Utility/TaskPool.cpp
===================================================================
--- source/Utility/TaskPool.cpp
+++ source/Utility/TaskPool.cpp
@@ -61,8 +61,9 @@
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();
}
}
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