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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 2DF22C433F5 for ; Wed, 5 Sep 2018 18:24:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB98B20652 for ; Wed, 5 Sep 2018 18:24:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB98B20652 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727660AbeIEWzV (ORCPT ); Wed, 5 Sep 2018 18:55:21 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:60291 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727195AbeIEWzV (ORCPT ); Wed, 5 Sep 2018 18:55:21 -0400 Received: from p4fea45ac.dip0.t-ipconnect.de ([79.234.69.172] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1fxcT8-0002EY-Rh; Wed, 05 Sep 2018 20:23:58 +0200 Date: Wed, 5 Sep 2018 20:23:57 +0200 (CEST) From: Thomas Gleixner To: Prakruthi Deepak Heragu cc: linux-kernel@vger.kernel.org, ckadabi@codeaurora.org, tsoni@codeaurora.org, bryanh@codeaurora.org, Prasad Sodagudi Subject: Re: [PATCH] genirq: Avoid race between cpu hot plug and irq_desc() allocation paths In-Reply-To: <1536167131-20585-1-git-send-email-pheragu@codeaurora.org> Message-ID: References: <1536167131-20585-1-git-send-email-pheragu@codeaurora.org> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 5 Sep 2018, Prakruthi Deepak Heragu wrote: > One of the cores might have just allocated irq_desc() and other core > might be doing irq migration in the hot plug path. In the hot plug path > during the IRQ migration, for_each_active_irq macro is trying to get > irqs whose bits are set in allocated_irqs bit map but there is no return > value check after irq_to_desc for desc validity. Confused. All parts involved, irq allocation/deallocation and the CPU hotplug code take sparse_irq_lock to prevent exavtly that. Thanks, tglx