From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id jOOMHDkf12AoUQAAWB0awg (envelope-from ) for ; Sat, 26 Jun 2021 08:36:09 -0400 Received: by simark.ca (Postfix, from userid 112) id 668481F1F2; Sat, 26 Jun 2021 08:36:09 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,RDNS_DYNAMIC,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (ip-8-43-85-97.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id C63CD1E01F for ; Sat, 26 Jun 2021 08:36:05 -0400 (EDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 489DE383B40E for ; Sat, 26 Jun 2021 12:36:05 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 489DE383B40E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1624710965; bh=iuT7ONZp4zIjyW1odgrcHGXmLLE027WLGbUzlJQBTAE=; h=Subject:To:References:Date:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=WNYx5BWIc0Mw4ZQZ3D6IYD4KxEXhfe/AUaKYChRfvNp1rHegeL8NXKryZXJI3Tvnq WfUmTblcC+30n1QYraK9yUWOadBXe/VhqiFIgHXcYE4nCgP8vH+YnRKTTgYFSE8qDe 9VqLHCT/w6XQq3rwGI2f4peN4ErHZLiAtxlsEFzs= Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id 8A5EC3861800 for ; Sat, 26 Jun 2021 12:35:37 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 8A5EC3861800 Received: from simark.ca (simark.ca [158.69.221.121]) (authenticated bits=0) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 15QCZUEU012022 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 26 Jun 2021 08:35:34 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 15QCZUEU012022 Received: from [10.0.0.11] (192-222-157-6.qc.cable.ebox.net [192.222.157.6]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id ED5F71E01F; Sat, 26 Jun 2021 08:35:29 -0400 (EDT) Subject: Re: [PATCH 3/4] scoped_ignore_signal: Use sigprocmask+sigtimedwait instead of signal To: Pedro Alves , gdb-patches@sourceware.org References: <20210615111429.1879286-1-pedro@palves.net> <20210615111429.1879286-4-pedro@palves.net> Message-ID: Date: Sat, 26 Jun 2021 08:35:29 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210615111429.1879286-4-pedro@palves.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Poly-FromMTA: (simark.ca [158.69.221.121]) at Sat, 26 Jun 2021 12:35:30 +0000 X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Simon Marchi via Gdb-patches Reply-To: Simon Marchi Errors-To: gdb-patches-bounces+public-inbox=simark.ca@sourceware.org Sender: "Gdb-patches" On 2021-06-15 7:14 a.m., Pedro Alves wrote: > The problem with using signal(...) to temporarily ignore a signal, is > that that changes the the signal disposition for the whole process. > If multiple threads do it at the same time, you have a race. > > Fix this by using sigprocmask + sigtimedwait to implement the ignoring > instead, if available, which I think probably means everywhere except > Windows nowadays. This way, we only change the signal mask for the > current thread, so there's no race. I tried to build on macOS today and got: CXX compile/compile.o In file included from /Users/smarchi/src/binutils-gdb/gdb/compile/compile.c:46: /Users/smarchi/src/binutils-gdb/gdb/../gdbsupport/scoped_ignore_signal.h:69:4: error: use of undeclared identifier 'sigtimedwait' sigtimedwait (&set, nullptr, &zero_timeout); ^ I didn't have time to dig yet. Simon