From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D1A4B377031 for ; Mon, 2 Mar 2026 07:31:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772436705; cv=none; b=E6yff6c/De59LIT1If4oLPJMH2olF3RJRiOfjwz33TmTIac2JeZDfJQ0J8MOT9uNemKSIr/ABkZjJHqi/qANC9eN4P2ZH+2Ucq25Jo0AdNmGk9MRSygscqeFBf3tPozis/h8WVgiEeZfsnnCQ3wFO8lbe0OK7u5NVYPK3cyYX+E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772436705; c=relaxed/simple; bh=XOIblyUY+naLJJGY0zT6QLnh9tXIuMGdvNV4ZdV35Sc=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=MAS6H1HCScDeCA0d+ET3Cf+ybsMRvJthgwKUlLEpEWtOB+aRQfy4uh4f4j3r5+wTkeJpkWnbYnVAHcey917BWlDbsN8UNqmuP+yGttc/t5kjZEZ1iMLxKCXeBdv421JtCsyMMIGkog/JnQzD/DlxqkdfBL2RiiX1kl30ZpfAcoQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=WcNz45+C; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WcNz45+C" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1772436703; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/2wTkJjwuYIbXyYb8D2J2N4b7CfFVskYwBA2k1/L4eQ=; b=WcNz45+CG4TglikNvnexWeLlmWd4Fgl6I3WlrWKdAtOz15E4oDLAUr4C466oGtQZbBsXXg HgI7HXM+FNMbzs1a3FvRE8/Vit5h3XUlY95fwHB+aL/DZGbpliNEKJAGn2Ln37GRvpEk7p 1Z0VHaow+I+71HHmdRSkxu7W7PWCjxI= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-451-eGML8WRiM8-J2d48TsPXdA-1; Mon, 02 Mar 2026 02:31:39 -0500 X-MC-Unique: eGML8WRiM8-J2d48TsPXdA-1 X-Mimecast-MFC-AGG-ID: eGML8WRiM8-J2d48TsPXdA_1772436697 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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 mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5478F18004BB; Mon, 2 Mar 2026 07:31:35 +0000 (UTC) Received: from fweimer-oldenburg.csb.redhat.com (unknown [10.44.32.151]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 243EA30001B9; Mon, 2 Mar 2026 07:31:26 +0000 (UTC) From: Florian Weimer To: Mathieu Desnoyers Cc: =?utf-8?Q?Andr=C3=A9?= Almeida , kernel-dev@igalia.com, "Liam R . Howlett" , linux-api@vger.kernel.org, Darren Hart , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Torvald Riegel , Davidlohr Bueso , Lorenzo Stoakes , Rich Felker , Carlos O'Donell , Michal Hocko , linux-kernel@vger.kernel.org, libc-alpha@sourceware.org , Arnd Bergmann , Sebastian Andrzej Siewior Subject: Re: [RFC PATCH 0/2] futex: how to solve the robust_list race condition? In-Reply-To: <694424f4-20d1-4473-8955-859acbad466f@efficios.com> (Mathieu Desnoyers's message of "Sun, 1 Mar 2026 10:49:15 -0500") References: <20260220202620.139584-1-andrealmeid@igalia.com> <0d334517-63ee-46c9-884d-6c2ae8388b87@efficios.com> <67be0aa1-2241-43ef-aa01-a89ced26c8f6@efficios.com> <694424f4-20d1-4473-8955-859acbad466f@efficios.com> Date: Mon, 02 Mar 2026 08:31:24 +0100 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 * Mathieu Desnoyers: > Of course, we'd have to implement the whole transaction in assembler > for each architecture. Could this be hidden ina vDSO call? It would have to receive a pointer to the rseq area in addition to other arguments that identify the unlock operation to be performed. The advantage is that the kernel would now the addresses involved, so a single rseq flag should be sufficient. It could also vary the LL/SC sequence based on architecture capabilities. The question is whether we can model the unlock operation so that it's sufficiently generic. Thanks, Florian