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From: Alexandre Oliva <aoliva@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc(refs/users/aoliva/heads/testme)] [libstdc++] ensure mutex_pool survives _Safe_sequence_base Date: Thu, 16 Feb 2023 11:13:47 +0000 (GMT) [thread overview] Message-ID: <20230216111347.1E5B43857C55@sourceware.org> (raw) https://gcc.gnu.org/g:e298c760cab78f831cd25d398636f4b8befc88a7 commit e298c760cab78f831cd25d398636f4b8befc88a7 Author: Alexandre Oliva <oliva@adacore.com> Date: Thu Feb 16 07:45:40 2023 -0300 [libstdc++] ensure mutex_pool survives _Safe_sequence_base On vxworks, after destroying the semaphore used to implement a mutex, __gthread_mutex_lock fails and __gnu_cxx::__mutex::lock calls __throw_concurrence_lock_error. Nothing ensures the mutex_pool mutexes survive init-once objects containing _Safe_sequence_base. If such an object completes construction before mutex_pool initialization, it will be registered for atexit destruction after the mutex_pool mutexes, so the _M_detach_all() call in the _Safe_sequence_base dtor will use already-destructed mutexes, and basic_string/requirements/citerators_cc fails calling terminate. This patch fixes this problem by ensuring the mutex pool completes construction before any _Safe_sequence_base-containing object, so that the mutex pool survives them all. for libstdc++-v3/ChangeLog * include/debug/safe_base.h (_Safe_sequence_base): Ensure the mutex pool survives *this. Diff: --- libstdc++-v3/include/debug/safe_base.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/libstdc++-v3/include/debug/safe_base.h b/libstdc++-v3/include/debug/safe_base.h index 1dfa9f68b65..d4ba404cdac 100644 --- a/libstdc++-v3/include/debug/safe_base.h +++ b/libstdc++-v3/include/debug/safe_base.h @@ -203,7 +203,15 @@ namespace __gnu_debug // Initialize with a version number of 1 and no iterators _Safe_sequence_base() _GLIBCXX_NOEXCEPT : _M_iterators(0), _M_const_iterators(0), _M_version(1) - { } + { + // Make sure the mutex_pool machinery is initialized before any + // full object containing a _Safe_sequence_base completes + // construction, so that any local static mutexes in the mutex + // pool won't be destructed before our destructor runs; + // _M_detach_all could fail otherwise, on targets whose mutexes + // stop working after being destroyed. + (void)this->_M_get_mutex(); + } #if __cplusplus >= 201103L _Safe_sequence_base(const _Safe_sequence_base&) noexcept
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