From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2140) id 3038D3857C55; Thu, 16 Feb 2023 11:13:52 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 3038D3857C55 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1676546032; bh=Mqe0tmAerGRv/nPgJVZpf7zs6CN4Ke9Hi/OVWB8cqL4=; h=From:To:Subject:Date:From; b=Q81P/2qMH4O/u4YzoCqM/aaPak0+AxQlziHQFR8pkFZu3PwhieIBnhw4ioB3n6nAm 68dJLjNS7DzcRYnQvB3RcJKHsIpBKiJkud7fULlgFh36xKI9Q4QzWAnA+rgq3eu3Z7 U8v7kdAOiFWEQqzhKn61UZnWKn4r0uI9C+0e6hck= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Alexandre Oliva To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc(refs/users/aoliva/heads/testme)] [libstdc++] do not destruct mutex_pool mutexes X-Act-Checkin: gcc X-Git-Author: Alexandre Oliva X-Git-Refname: refs/users/aoliva/heads/testme X-Git-Oldrev: e298c760cab78f831cd25d398636f4b8befc88a7 X-Git-Newrev: f7fc3cbf626dd41ba4fe1cfba8a23a1236f89e4e Message-Id: <20230216111352.3038D3857C55@sourceware.org> Date: Thu, 16 Feb 2023 11:13:52 +0000 (GMT) List-Id: https://gcc.gnu.org/g:f7fc3cbf626dd41ba4fe1cfba8a23a1236f89e4e commit f7fc3cbf626dd41ba4fe1cfba8a23a1236f89e4e Author: Alexandre Oliva Date: Thu Feb 16 07:45:43 2023 -0300 [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. Diff: --- libstdc++-v3/src/c++11/shared_ptr.cc | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/libstdc++-v3/src/c++11/shared_ptr.cc b/libstdc++-v3/src/c++11/shared_ptr.cc index bc70134359c..74e879e5828 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]; } }