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author | Alexandre Oliva <oliva@adacore.com> | 2023-02-22 14:35:18 -0300 |
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committer | Alexandre Oliva <oliva@gnu.org> | 2023-02-22 14:38:17 -0300 |
commit | d70f49e98245f80fcf8b2e68a9f06955f52e1de7 (patch) | |
tree | 93bdea2b13844a22c91ff9395678592cec06e7e2 /libstdc++-v3 | |
parent | 2ff710857fd315770d71061e1a938324c1654d81 (diff) | |
download | gcc-d70f49e98245f80fcf8b2e68a9f06955f52e1de7.zip gcc-d70f49e98245f80fcf8b2e68a9f06955f52e1de7.tar.gz gcc-d70f49e98245f80fcf8b2e68a9f06955f52e1de7.tar.bz2 |
[libstdc++] do not destruct mutex_pool mutexes
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 mutexes are
constructed on demand, on a statically-allocated buffer, but never
destructed.
for libstdc++-v3/ChangeLog
* src/c++11/shared_ptr.cc (__gnu_internal::get_mutex):
Avoid destruction of the mutex pool.
Diffstat (limited to 'libstdc++-v3')
-rw-r--r-- | libstdc++-v3/src/c++11/shared_ptr.cc | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/libstdc++-v3/src/c++11/shared_ptr.cc b/libstdc++-v3/src/c++11/shared_ptr.cc index bc70134..74e879e 100644 --- a/libstdc++-v3/src/c++11/shared_ptr.cc +++ b/libstdc++-v3/src/c++11/shared_ptr.cc @@ -36,7 +36,11 @@ namespace __gnu_internal _GLIBCXX_VISIBILITY(hidden) { // increase alignment to put each lock on a separate cache line struct alignas(64) M : __gnu_cxx::__mutex { }; - static M m[mask + 1]; + // Use a static buffer, so that the mutexes are not destructed + // before potential users (or at all) + static __attribute__ ((aligned(__alignof__(M)))) + char buffer[(sizeof (M)) * (mask + 1)]; + static M *m = new (buffer) M[mask + 1]; return m[i]; } } |