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=-13.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 4BAF6C4320A for ; Wed, 18 Aug 2021 11:38:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2807B6102A for ; Wed, 18 Aug 2021 11:38:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235528AbhHRLi7 (ORCPT ); Wed, 18 Aug 2021 07:38:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:35566 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233798AbhHRLi6 (ORCPT ); Wed, 18 Aug 2021 07:38:58 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5737F60FDA; Wed, 18 Aug 2021 11:38:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629286703; bh=aDzfwtEULpUKTJYRxiVnKDspw5jwJLol+Nu/stmLGaA=; h=Date:From:To:Cc:Subject:From; b=NPhTg2D9Edg2nA+5i65ORZv3IPK7Bs6COSJyqM2lmWinyVWpE0rYKiHlRU62xawgA iVDlpCFWUpd7V4IMGq4xIKsG7z+opebdsvr5qDssHsyp+zh7rE9ei34gVQNhQYa9sN H+kAcQSrPPdT4Yva2jyigJychlcpzX5yQEoCy/4HvOrMtcdkYcy4tqjBGqmsRGVtHY +pHdvFCAdcYI3X2g/rF+Ds00oJp+vC7/woZ5YKKy5qmZ0FMMfgGT04mgZRUnb+p+rs sIeY2Kk/mdo7am4oF09mzkdcVIsNzIPlPtp0eTfdsNLI0qj6eRPmQJybFG+yNvgYIQ mrep56/wpBJag== Received: by pali.im (Postfix) id CCA6768A; Wed, 18 Aug 2021 13:38:20 +0200 (CEST) Date: Wed, 18 Aug 2021 13:38:20 +0200 From: Pali =?utf-8?B?Um9ow6Fy?= To: Kunihiko Hayashi Cc: Marc Zyngier , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: pcie-uniphier: race condition in masking/unmasking interrupts Message-ID: <20210818113820.fzjeouy6tohbzuad@pali> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: NeoMutt/20180716 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! Marc pointed during review of pci-aardvark patches one issue which I see that is available also in the current pcie-uniphier.c driver. When masking or unmasking interrupts there is read-modify-write sequence for PCL_RCV_INTX_MASK_SHIFT register without any locking: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/controller/dwc/pcie-uniphier.c?h=v5.13#n171 So when trying to mask/unmask two interrupts at the same time there is race condition as updating that PCL_RCV_INTX_MASK_SHIFT register is not atomic. Could you look at it?