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bh=U4VXwNM3yP1Pd06ut1KyJ/qoGEtR/Z9rA18OSI0FddM=; b=Cdms3YVHZgqoj2yGIjG9MXzz1fO8Awt2vm+9yI9N71TiT7+FfPPRx3qRtNUWX4UrgA1Y3z 7bph2/0XFHswttdNLZUrSLxJSFRBSBbkEyEjrNT4VWIBdjjXNvbS2F7eK/+jxZbc/8fvZ2 Lj+M5SJ+ryazaVbux0DC2mdAhAarjf4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-465-OZgOnzEjPLillbQP29Jvtw-1; Thu, 21 Jan 2021 11:04:51 -0500 X-MC-Unique: OZgOnzEjPLillbQP29Jvtw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D72D11015940 for ; Thu, 21 Jan 2021 16:04:50 +0000 (UTC) Received: from redhat.com (ovpn-115-126.ams2.redhat.com [10.36.115.126]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A3FED10016F5; Thu, 21 Jan 2021 16:04:46 +0000 (UTC) Date: Thu, 21 Jan 2021 16:04:43 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Max Reitz Subject: Re: Thread safety of coroutine-sigaltstack Message-ID: <20210121160443.GO3125227@redhat.com> References: <7b8155ad-0942-dc1c-f43c-bb5eb518a278@redhat.com> <445268c9-d91f-af5a-3d7e-f4c6f014ca52@redhat.com> <62d5d33c-fe2a-228b-146d-632c84d09fd5@redhat.com> <823a843f-af47-f091-1bd1-e33487524eb9@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.168, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Kevin Wolf , Laszlo Ersek , "qemu-devel@nongnu.org" , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Jan 21, 2021 at 04:42:09PM +0100, Max Reitz wrote: > On 21.01.21 14:34, Laszlo Ersek wrote: > > On 01/21/21 10:27, Max Reitz wrote: > > SUSv3 marked ucontext functions obsolescent: > > > > https://pubs.opengroup.org/onlinepubs/000095399/functions/makecontext.html#tag_03_356_08 > > > > and they are entirely missing from SUSv4 (aka the latest POSIX): > > > > https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xsh_chap03.html#tag_22_03_01_07 > > > > So you can use ucontext if you #define _XOPEN_SOURCE as 500 or 600, but > > (in theory) not if you #define it as 700. How this works out in practice > > on OSX -- i.e. how long they intend to support _XOPEN_SOURCE 600 --, I > > can't tell. > > Daniel made it sound like there was a libucontext that might be the way to > go forward. > > > I don't disagree with Daniel though; you can always bring back > > coroutine-sigaltstack from the git history, if Apple decides to drop > > ucontext. > > It may be a bit more hassle (the configure option has to be removed, then > maybe readded), but, well, yes. ucontext on macOS may be slightly harder than i imagined. While making it compile is easy, the qtests then hang so there's something not quite right on macOS with ucontext and it basically impossible to debug in Cirrus CI I still think it is worth exploring, but it will require someone with direct access to a macOS env to debug this I think. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|