From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rock.gnat.com (rock.gnat.com [IPv6:2620:20:4000:0:a9e:1ff:fe9b:1d1]) by sourceware.org (Postfix) with ESMTPS id 409DD3841459; Tue, 21 Jun 2022 06:03:49 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 409DD3841459 Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id 05A251160D8; Tue, 21 Jun 2022 02:03:49 -0400 (EDT) X-Virus-Scanned: Debian amavisd-new at gnat.com Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id iPgkBxiXPjHv; Tue, 21 Jun 2022 02:03:48 -0400 (EDT) Received: from free.home (tron.gnat.com [IPv6:2620:20:4000:0:46a8:42ff:fe0e:e294]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by rock.gnat.com (Postfix) with ESMTPS id C31801160B7; Tue, 21 Jun 2022 02:03:48 -0400 (EDT) Received: from livre (livre.home [172.31.160.2]) by free.home (8.15.2/8.15.2) with ESMTPS id 25L63fVB693603 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 21 Jun 2022 03:03:41 -0300 From: Alexandre Oliva To: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org Subject: [PATCH] libstdc++: eh_globals: gthreads: reset _S_init before deleting key Organization: Free thinker, does not speak for AdaCore Errors-To: aoliva@lxoliva.fsfla.org Date: Tue, 21 Jun 2022 03:03:41 -0300 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 X-Spam-Status: No, score=-12.3 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libstdc++@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++ mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Jun 2022 06:03:59 -0000 Clear __eh_globals_init's _S_init in the dtor before deleting the gthread key. This ensures that, in case any code involved in deleting the key interacts with eh_globals, the key that is being deleted won't be used, and the non-thread-specific eh_globals fallback will. Regstrapped on x86_64-linux-gnu, also tested with a cross to aarch64-rtems6. Ok to install? PS: This is a fix for a theoretical issue, that came to mind while I independently investigated the problem that I later found to be PR105880. for libstdc++-v3/ChangeLog * libsupc++/eh_globals.cc [!_GLIBCXX_HAVE_TLS] (__eh_globals_init::~__eh_globals_init): Clear _S_init first. --- libstdc++-v3/libsupc++/eh_globals.cc | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/libsupc++/eh_globals.cc b/libstdc++-v3/libsupc++/eh_globals.cc index 768425c0f407a..0aadb692a9625 100644 --- a/libstdc++-v3/libsupc++/eh_globals.cc +++ b/libstdc++-v3/libsupc++/eh_globals.cc @@ -119,8 +119,13 @@ struct __eh_globals_init ~__eh_globals_init() { if (_S_init) - __gthread_key_delete(_M_key); - _S_init = false; + { + /* Set it before the call, so that, should + __gthread_key_delete throw an exception, it won't rely on + the key being deleted. */ + _S_init = false; + __gthread_key_delete(_M_key); + } } __eh_globals_init(const __eh_globals_init&) = delete; -- Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/ Free Software Activist GNU Toolchain Engineer Disinformation flourishes because many people care deeply about injustice but very few check the facts. Ask me about