From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B3E9C41513 for ; Tue, 15 Aug 2023 11:18:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236699AbjHOLSM (ORCPT ); Tue, 15 Aug 2023 07:18:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236689AbjHOLRS (ORCPT ); Tue, 15 Aug 2023 07:17:18 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 880E3EE for ; Tue, 15 Aug 2023 04:17:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Subject:Cc:To:From:Date:Message-ID: Sender:Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To:References; bh=8earX3r0sIh2/8rl9iwG2HlAaQmkPP9fYoiwKlrBrYg=; b=NOBKhMVdmQxKQn/SrJb6yeL7Mk rrK/A8cOAea4SJKbmpW4OouH++Y+QnQ1tYq1BCYNizawidGl1mAwB5rw2MVzffH8b1WriFJ+NdXF1 vOsRjjhaPmOp6UYz5ayvaqWIXzpmcEmtqOKK+M+GPbgYO7Xuo9S74r5jw1nAN5C+QTUIRV3FB4vxH 0ZVKmhHubENAoLy2/GtAbC+SNA///7ArStI7x7tLEboHjwed928twl5rofNYZTjbhN8kPcqOwb07Y 6dxYuzZ6Jc82HpOtc1rLrLui7UwU/zlie0DG9hG/Nr4A2FBkgzFjn+PeUW6QAhf2q+bf+jyhUsGJS hoUlUrrw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qVs2c-00Bo43-0H; Tue, 15 Aug 2023 11:16:53 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 0F61B30020B; Tue, 15 Aug 2023 13:16:49 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id E53662074B3D8; Tue, 15 Aug 2023 13:16:48 +0200 (CEST) Message-ID: <20230815110121.117752409@infradead.org> User-Agent: quilt/0.66 Date: Tue, 15 Aug 2023 13:01:21 +0200 From: Peter Zijlstra To: bigeasy@linutronix.de, tglx@linutronix.de Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, bsegall@google.com, boqun.feng@gmail.com, swood@redhat.com, bristot@redhat.com, dietmar.eggemann@arm.com, mingo@redhat.com, jstultz@google.com, juri.lelli@redhat.com, mgorman@suse.de, rostedt@goodmis.org, vschneid@redhat.com, vincent.guittot@linaro.org, longman@redhat.com, will@kernel.org Subject: [PATCH 0/6] locking/rtmutex: Avoid PI state recursion through sched_submit_work() Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! This is basically the 'same' patches as send earlier by Sebastian here: https://lkml.kernel.org/r/20230427111937.2745231-1-bigeasy@linutronix.de I spend a number of days trying to invert rtmutex, only to make a giant mess of things and finally conceded that this is the least horrible approach. There's a bunch of naming differences and I added some asserts that should hopefully avoid things from going sideways without notice. I've also updated the changelogs to high-light the actual problem. The whole pi_blocked_on 'corruption' is a mere consequence of the more fundamental problem that the whole PI state recurses. I've not tested this with the rest of the RT patches stuck on, so very limited actual testing happened. If anybody could please confirm stuff still works as advertised, I'll go queue this mess and we can hopefully forget all about it.