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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 38C4AC2B9F4 for ; Sat, 19 Jun 2021 11:37:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17B01601FF for ; Sat, 19 Jun 2021 11:37:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233925AbhFSLjt (ORCPT ); Sat, 19 Jun 2021 07:39:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230437AbhFSLjs (ORCPT ); Sat, 19 Jun 2021 07:39:48 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0DEEC061574 for ; Sat, 19 Jun 2021 04:37:37 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1624102654; 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=ums+h3Qr4LeMZdW3sa2+1i2S4XpLBjN7KS0U3VAjUCc=; b=TDFuKC2NjnHaaPfa3ipTmLHktR1lXcAl4IiUrBoa+5fZ3fuN3QoM0h3hYSu/jbWaichDUS X+2/o8O5enb091NmBaEtTiFgVHfvN++EVfBElBYYNf+0rlpsr10UCMlgE3M1QA5uoYhDJ2 wfz2lYmyURjV5aOh2gop5OcVO/u+9K871feHYeXidbNld3dPNFjWvb36xzh5Y/5pxINP5T 1BKsVeVkecYJfzEMjpRT8nJtdaHmZSzs0vLl3asOL//4JXvUjtxQ71z+UwyCDkBstAl2T3 MHSEzG3OMGAluJgEWg2QVI5+rz0RbkfqS3qqkAJpoHclH5hcj/mloqYfwBx/fg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1624102654; 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=ums+h3Qr4LeMZdW3sa2+1i2S4XpLBjN7KS0U3VAjUCc=; b=QljFLa8+AHJO0aSz3EEe7DT8kh3JVsUemjJQxevrjWPntcFXkCAuCAxBCOcrE1QU8xsM1H AvkwvB3KDJm9R9Cg== To: Marc Zyngier , linux-kernel@vger.kernel.org Cc: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Ley Foon Tan , Chris Zankel , Max Filippov , Vineet Gupta , Thomas Bogendoerfer , Robert Jarzmik , Russell King , Krzysztof Kozlowski , Yoshinori Sato , Rich Felker , Geert Uytterhoeven , Alex Deucher , Christian =?utf-8?Q?K=C3=B6nig?= , David Airlie , Daniel Vetter , Rob Clark , Linus Walleij , Lee Jones , Lorenzo Pieralisi , Rob Herring , Bjorn Helgaas , Bartosz Golaszewski , kernel-team@android.com Subject: Re: [PATCH 20/39] irqdomain: Protect the linear revmap with RCU In-Reply-To: <20210520163751.27325-21-maz@kernel.org> References: <20210520163751.27325-1-maz@kernel.org> <20210520163751.27325-21-maz@kernel.org> Date: Sat, 19 Jun 2021 13:37:33 +0200 Message-ID: <87zgvmccg2.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 20 2021 at 17:37, Marc Zyngier wrote: > static void irq_domain_clear_mapping(struct irq_domain *domain, > @@ -902,12 +901,12 @@ unsigned int irq_find_mapping(struct irq_domain *domain, > return 0; > } > > + rcu_read_lock(); > /* Check if the hwirq is in the linear revmap. */ > if (hwirq < domain->revmap_size) > - return domain->revmap[hwirq]->irq; > - > - rcu_read_lock(); > - data = radix_tree_lookup(&domain->revmap_tree, hwirq); > + data = rcu_dereference(domain->revmap[hwirq]); > + else > + data = radix_tree_lookup(&domain->revmap_tree, hwirq); > rcu_read_unlock(); > return data ? data->irq : 0; This is wrong and was wrong before. This wants to be: irq = data ? data->irq : 0; rcu_read_unlock(); return irq; Thanks, tglx