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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57521C4742C for ; Tue, 10 Nov 2020 11:39:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6B3720659 for ; Tue, 10 Nov 2020 11:39:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="XFDkZZh7"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="hzp07aYi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730370AbgKJLjD (ORCPT ); Tue, 10 Nov 2020 06:39:03 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:57826 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726721AbgKJLjC (ORCPT ); Tue, 10 Nov 2020 06:39:02 -0500 From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1605008340; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=V5tgrA9mzGrDzhEZn2WdPClqxxggWGyrkJ8LW+RVJ5E=; b=XFDkZZh7VfYQNeF3TtmrTaKsNJJQRRoTs0Qsj0R7LhOoybDpj9iUwWAGmjamJUrpnp3QPA 0RTGux80GFcHV92zQrwh5jLVhmxHGnmuSEVKwMSNvSM7GBac/VRUwKZEgWGAmJTy7WHN6K uH8+BYGnOKOG9Q+46EoGulUt/q0fD9Sb8vQWU3usPvMeGMcLN3TxCZ/yyVtU8pgAJkJ3tB 3lgct1qDhdAjcSSxUZyVz22xM+UwvCEerk2eBYKA9dXizTgeN0SecaNH/DGz9TMQGMiMgy uUkjlSXk8XjW0tJwWSnLqw1UbiulcKZIlHZJcgwZoHjwkorjIgFiCxZeiC08TA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1605008340; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=V5tgrA9mzGrDzhEZn2WdPClqxxggWGyrkJ8LW+RVJ5E=; b=hzp07aYixIJ62foUWVnsOuaUAURo3cMN5AUfaEnLRymMSkq1/OyTC2PCXFUTD24zZovMCk 163f3zKhIuYVfkCA== To: linux-kernel@vger.kernel.org Cc: Thomas Gleixner , Peter Zijlstra , Ben Skeggs , Mike Galbraith Subject: [PATCH 0/2] genirq: Move prio assignment into the newly created thread Date: Tue, 10 Nov 2020 12:38:46 +0100 Message-Id: <20201110113848.801379-1-bigeasy@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mike reported [0] a lockdep splat triggered by the nouveau driver together with enabled threaded interrupts. I can't easily tell if moving / changing locking within nouveau does not break anything and does not create the same lockchain in another path. Mike did confirm that the lockdep splat can be avoided by by moving `request_irq()' out of the picture [1]. He also tested the two patches which are scattered in the thread. Mike is betting on commit 710da3c8ea7df ("sched/core: Prevent race condition between cpuset and __= sched_setscheduler()") as the source change that introduce that problem assuming that locking within the nouveau remained unchanged. He did confirm that this splat exists also in a v5.4 stable kernel [2] which is where the change was introduced. [0] https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.came= l@gmx.de [1] https://lkml.kernel.org/r/431e81699f2310eabfe5af0a3de400ab99d9323b.came= l@gmx.de [2] https://lkml.kernel.org/r/f7e43b369c7d168c2ff04bfd91dfdf3afd0da12c.came= l@gmx.de Sebastian