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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 67513C433E1 for ; Mon, 15 Jun 2020 20:54:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41DC320768 for ; Mon, 15 Jun 2020 20:54:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731104AbgFOUyR (ORCPT ); Mon, 15 Jun 2020 16:54:17 -0400 Received: from mga18.intel.com ([134.134.136.126]:36796 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726207AbgFOUyQ (ORCPT ); Mon, 15 Jun 2020 16:54:16 -0400 IronPort-SDR: sM5Mtun9sUrTRP+w60RESw1pGYEDdq1fTwSvxtVgafQHHIJM84b/1Ei/JYqhE/g/LT0JVnePfD kDCZLG35up3Q== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2020 13:54:15 -0700 IronPort-SDR: tF1mCDx4+4odW013lV1xxu0FxwXD3sjeJh4tTKUBVFCX5x1WWTcaR891pp3TLnydTCUJCjQnwc ENFW8iTG9BMA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,516,1583222400"; d="scan'208";a="298652675" Received: from djiang5-desk3.ch.intel.com ([143.182.136.137]) by fmsmga004.fm.intel.com with ESMTP; 15 Jun 2020 13:54:15 -0700 Subject: [PATCH] dmaengine: idxd: fix cdev locking for open and release From: Dave Jiang To: vkoul@kernel.org Cc: Nikhil Rao , dmaengine@vger.kernel.org Date: Mon, 15 Jun 2020 13:54:15 -0700 Message-ID: <159225445529.68253.775183898115820961.stgit@djiang5-desk3.ch.intel.com> User-Agent: StGit/unknown-version MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org From: Nikhil Rao add the wq lock in cdev open and release call. This fixes race conditions observed in the open and close routines. Fixes: 42d279f9137a ("dmaengine: idxd: add char driver to expose submission portal to userland") Signed-off-by: Nikhil Rao Signed-off-by: Dave Jiang --- drivers/dma/idxd/cdev.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c index ff49847e37a8..207555296913 100644 --- a/drivers/dma/idxd/cdev.c +++ b/drivers/dma/idxd/cdev.c @@ -74,6 +74,7 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp) struct idxd_device *idxd; struct idxd_wq *wq; struct device *dev; + int rc; wq = inode_wq(inode); idxd = wq->idxd; @@ -81,17 +82,29 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp) dev_dbg(dev, "%s called: %d\n", __func__, idxd_wq_refcount(wq)); - if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq)) - return -EBUSY; + mutex_lock(&wq->wq_lock); + + if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq)) { + rc = -EBUSY; + goto failed; + } ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); - if (!ctx) - return -ENOMEM; + if (!ctx) { + rc = -ENOMEM; + goto failed; + } ctx->wq = wq; filp->private_data = ctx; idxd_wq_get(wq); + mutex_unlock(&wq->wq_lock); return 0; + + failed: + mutex_unlock(&wq->wq_lock); + kfree(ctx); + return rc; } static int idxd_cdev_release(struct inode *node, struct file *filep) @@ -105,7 +118,9 @@ static int idxd_cdev_release(struct inode *node, struct file *filep) filep->private_data = NULL; kfree(ctx); + mutex_lock(&wq->wq_lock); idxd_wq_put(wq); + mutex_unlock(&wq->wq_lock); return 0; }