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=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 5A020C43441 for ; Thu, 29 Nov 2018 14:20:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 226B420868 for ; Thu, 29 Nov 2018 14:20:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="yUwXZ9+1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 226B420868 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org 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 S1731300AbeK3BZr (ORCPT ); Thu, 29 Nov 2018 20:25:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:49222 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729806AbeK3BZr (ORCPT ); Thu, 29 Nov 2018 20:25:47 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A89A220868; Thu, 29 Nov 2018 14:20:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543501216; bh=L7mBtZQTKwdfLiC8MbkQAatAtYV5kkbn5565OAKjgc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yUwXZ9+1NHinp7/GqMFVMzi1sCscQ2czeKPWZI+u0eqoZjQydMRdVP9Efo9mTrxhJ vrfPs6DSCzO8OyV8bo3vejHhQY8SZrj816oal3WCLoJNnWCsc6hULttSKaLvTbZv+9 iM/C/R5PVM9h88jqLvHnx7N+ce9Uypzd12VIv1PY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Venkat Gopalakrishnan , Subhash Jadavani , "Martin K. Petersen" , Amit Pundir Subject: [PATCH 4.4 74/86] scsi: ufshcd: Fix race between clk scaling and ungate work Date: Thu, 29 Nov 2018 15:12:39 +0100 Message-Id: <20181129140115.897979142@linuxfoundation.org> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181129140109.832117862@linuxfoundation.org> References: <20181129140109.832117862@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Venkat Gopalakrishnan commit f2a785ac23125fa0774327d39e837e45cf28fe92 upstream. The ungate work turns on the clock before it exits hibern8, if the link was put in hibern8 during clock gating work. There occurs a race condition when clock scaling work calls ufshcd_hold() to make sure low power states cannot be entered, but that returns by checking only whether the clocks are on. This causes the clock scaling work to issue UIC commands when the link is in hibern8 causing failures. Make sure we exit hibern8 state before returning from ufshcd_hold(). Callstacks for race condition: ufshcd_scale_gear ufshcd_devfreq_scale ufshcd_devfreq_target update_devfreq devfreq_monitor process_one_work worker_thread kthread ret_from_fork ufshcd_uic_hibern8_exit ufshcd_ungate_work process_one_work worker_thread kthread ret_from_fork Signed-off-by: Venkat Gopalakrishnan Signed-off-by: Subhash Jadavani Signed-off-by: Martin K. Petersen Signed-off-by: Amit Pundir Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/ufs/ufshcd.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -585,6 +585,21 @@ int ufshcd_hold(struct ufs_hba *hba, boo start: switch (hba->clk_gating.state) { case CLKS_ON: + /* + * Wait for the ungate work to complete if in progress. + * Though the clocks may be in ON state, the link could + * still be in hibner8 state if hibern8 is allowed + * during clock gating. + * Make sure we exit hibern8 state also in addition to + * clocks being ON. + */ + if (ufshcd_can_hibern8_during_gating(hba) && + ufshcd_is_link_hibern8(hba)) { + spin_unlock_irqrestore(hba->host->host_lock, flags); + flush_work(&hba->clk_gating.ungate_work); + spin_lock_irqsave(hba->host->host_lock, flags); + goto start; + } break; case REQ_CLKS_OFF: if (cancel_delayed_work(&hba->clk_gating.gate_work)) {