From patchwork Mon Jan 10 18:47:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthias Kaehlcke X-Patchwork-Id: 12709052 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF6B4C433F5 for ; Mon, 10 Jan 2022 18:47:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242220AbiAJSrs (ORCPT ); Mon, 10 Jan 2022 13:47:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241560AbiAJSrr (ORCPT ); Mon, 10 Jan 2022 13:47:47 -0500 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D80FC061748 for ; Mon, 10 Jan 2022 10:47:47 -0800 (PST) Received: by mail-pj1-x102f.google.com with SMTP id y16-20020a17090a6c9000b001b13ffaa625so61132pjj.2 for ; Mon, 10 Jan 2022 10:47:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ShvwMaotgmHYVdyRN67h92I9DP3zj/wpQ1GkBlk/Io0=; b=bY3Jr6clk/F1DeLvYYTFQrOpmv3r+/HIgddPZvgbu9aU7WONBEcBhaxAx3gTkoKgUW rZEn23pieFdWmQP/CjGjD1akaeFOmUriPWVKAoxKRxh0H3k53xsZqK1leMpg9z8kxXeK BlWU1lQNk2TTML9iyGAIAXnvBh7NZvUJsg09M= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ShvwMaotgmHYVdyRN67h92I9DP3zj/wpQ1GkBlk/Io0=; b=hFlwzdaQyGKLJDhrAf8R8/Hb9R9008S+HJU7ggr6Ia9u1bJLBlOyWgMxgUNfHdl0Pb 3DFBEyz+rnYqduwqQ1Wv7ZWNR8/DLmPGuFTzI/n+/Vz9+2dfNdGwaLmlNfAOPeih+967 oQRQ03ot3BWBNGK1jcSKDtQjjAw0A4EVIu7TuyqXYl0+bO39xg0OATpZHq1b/OvlGIh/ ozqWP6z4YAyCY25tJmwRaLjGxg4CEsMstU+We0BkgGd4gDCPHume0F2x9r6HJFkKn9OT HMR6CZKyL5JHkGKjZAWVdmyS+wdies4WLTpdwn1WdgnEpXePXRcXrNMsVabas7X8vXDr Xk6A== X-Gm-Message-State: AOAM530UrOfCpERv2En1lLi13XXPcnzCLPwDWlmxbGnMXJ8faIc1GBvx m1JcbUXdkRpD+NqFdnIxB/Y4vw== X-Google-Smtp-Source: ABdhPJxderP7otW8Zajj9tFh0nOWHilY6JOnS9jnc7szLXg+tzFHs2CFgUsgiuNM5SOx2QsQuKyMnA== X-Received: by 2002:a17:90b:1e50:: with SMTP id pi16mr1104987pjb.118.1641840466651; Mon, 10 Jan 2022 10:47:46 -0800 (PST) Received: from localhost ([2620:15c:202:201:470e:3451:3aa4:4b43]) by smtp.gmail.com with UTF8SMTPSA id s35sm7393137pfw.193.2022.01.10.10.47.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 10 Jan 2022 10:47:45 -0800 (PST) From: Matthias Kaehlcke To: Andy Gross , Ohad Ben-Cohen Cc: Stephen Boyd , linux-kernel@vger.kernel.org, linux-remoteproc@vger.kernel.org, Sibi Sankar , Sujit Kautkar , Bjorn Andersson , Matthias Kaehlcke , Mathieu Poirier Subject: [PATCH v6 2/2] rpmsg: char: Fix race between the release of rpmsg_eptdev and cdev Date: Mon, 10 Jan 2022 10:47:37 -0800 Message-Id: <20220110104706.v6.2.Idde68b05b88d4a2e6e54766c653f3a6d9e419ce6@changeid> X-Mailer: git-send-email 2.34.1.575.g55b058a8bb-goog In-Reply-To: <20220110104706.v6.1.Iaac908f3e3149a89190ce006ba166e2d3fd247a3@changeid> References: <20220110104706.v6.1.Iaac908f3e3149a89190ce006ba166e2d3fd247a3@changeid> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org struct rpmsg_eptdev contains a struct cdev. The current code frees the rpmsg_eptdev struct in rpmsg_eptdev_destroy(), but the cdev is a managed object, therefore its release is not predictable and the rpmsg_eptdev could be freed before the cdev is entirely released. The cdev_device_add/del() API was created to address this issue (see commit 233ed09d7fda), use it instead of cdev add/del(). Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface") Suggested-by: Bjorn Andersson Signed-off-by: Matthias Kaehlcke Reviewed-by: Mathieu Poirier Reviewed-by: Bjorn Andersson Reviewed-by: Stephen Boyd --- Changes in v6: - remove cdev_del() from rpmsg_eptdev_release_device() - added 'Reviewed-by' tag from Mathieu and 'Suggested-by' tag Changes in v5: - patch added to the series drivers/rpmsg/rpmsg_char.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index ba85f5d11960..49dd5a200998 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -92,7 +92,7 @@ static int rpmsg_eptdev_destroy(struct device *dev, void *data) /* wake up any blocked readers */ wake_up_interruptible(&eptdev->readq); - device_del(&eptdev->dev); + cdev_device_del(&eptdev->cdev, &eptdev->dev); put_device(&eptdev->dev); return 0; @@ -335,7 +335,6 @@ static void rpmsg_eptdev_release_device(struct device *dev) ida_simple_remove(&rpmsg_ept_ida, dev->id); ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt)); - cdev_del(&eptdev->cdev); kfree(eptdev); } @@ -380,19 +379,13 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, dev->id = ret; dev_set_name(dev, "rpmsg%d", ret); - ret = cdev_add(&eptdev->cdev, dev->devt, 1); + ret = cdev_device_add(&eptdev->cdev, &eptdev->dev); if (ret) goto free_ept_ida; /* We can now rely on the release function for cleanup */ dev->release = rpmsg_eptdev_release_device; - ret = device_add(dev); - if (ret) { - dev_err(dev, "device_add failed: %d\n", ret); - put_device(dev); - } - return ret; free_ept_ida: