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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5ABEC433F5 for ; Fri, 11 Mar 2022 20:55:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230432AbiCKU4J (ORCPT ); Fri, 11 Mar 2022 15:56:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230055AbiCKU4G (ORCPT ); Fri, 11 Mar 2022 15:56:06 -0500 Received: from mail-oo1-xc2f.google.com (mail-oo1-xc2f.google.com [IPv6:2607:f8b0:4864:20::c2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0509202897 for ; Fri, 11 Mar 2022 12:54:52 -0800 (PST) Received: by mail-oo1-xc2f.google.com with SMTP id s203-20020a4a3bd4000000b003191c2dcbe8so11890483oos.9 for ; Fri, 11 Mar 2022 12:54:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=1Eb4lJ/gRDGHQtzxeJ/n15BUoLk+AfXEc1aV/y6NJFo=; b=mD6CQw0YWd3H8i8Emv3nPIRx2chGxuqbAk1C75U0CqzBBTn9zloG/aU5nIwgWuMjxc UNkPmd8Pwd4Duvvp6MIgSvRF6LPOgQQ8aG12+/IS04ubDMbb1ZXfGGjaA+V2hEqhdMsF L7Iw19u8joHut2ekiM4dK6FMbRZ4wGH6jP3ps9KWjKXPkFzGEMw/DcjRDwxmpRY0vZE2 qOEDk0a1Bh8kjMzxvUa+36rTE9pdSV+DJ8IfrmBQhLYiJucMJEXg+S7RYm8+h5JukFhL IC0hP3TnWoHw+wu0sPhi7zeITEXSB32A3lFsLhZ5MxwhDSvp5v6S+59ACGi6RfgRkEHh 7klQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=1Eb4lJ/gRDGHQtzxeJ/n15BUoLk+AfXEc1aV/y6NJFo=; b=6KKAABymygmrSqKGjB8HbiNekmzKQNqKYPJmhOHazz2wqoklD9+lOG4NjLCY1Qe1AS sDvoDIWCnzKi2APwbPgrMwTJPDZjAUrC83QPDHqj6wG+9Qored94QlvHiYuhOg3EHst8 OtrbdRTP8E/gHQxtoOVMUF1fd/4bpahbiqket8AFvHJckC5tH5Nt0Pa3cKMR+3P/gx+0 HNJYLKEWKwj6ig01jA/0M9zNhHdOxOh8F2PiFPufEHzFQW9c/8J5SWriVYu4+QB1uLUc gJ8Qjs6yfh6ibT8s7SkWb9SMoD5eD4vcgz7PlVEtMK64YA1EF/jhBqf47SOWw626T5z6 CHYg== X-Gm-Message-State: AOAM530wmxeDzllVJIzcvp8Yen+ECmzgIctvHXCawmG98k7zVCp5wYoT GZuCfm4ITNydL5NTGPWHRessX5tm5DmiFQ== X-Google-Smtp-Source: ABdhPJy5GmX5UQ0mj0ySsNzmIfZIFATXV7mzuj3RfTYMC74asWaMPo8GP7EpX/K3319p7uZfI+aziQ== X-Received: by 2002:a05:6870:a986:b0:da:b3f:3277 with SMTP id ep6-20020a056870a98600b000da0b3f3277mr6854732oab.295.1647032089018; Fri, 11 Mar 2022 12:54:49 -0800 (PST) Received: from builder.lan ([2600:1700:a0:3dc8:3697:f6ff:fe85:aac9]) by smtp.gmail.com with ESMTPSA id o10-20020acaf00a000000b002da04e165a4sm4245817oih.23.2022.03.11.12.54.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 11 Mar 2022 12:54:48 -0800 (PST) Date: Fri, 11 Mar 2022 14:54:46 -0600 From: Bjorn Andersson To: Deepak Kumar Singh Cc: swboyd@chromium.org, quic_clew@quicinc.com, mathieu.poirier@linaro.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-remoteproc@vger.kernel.org, Ohad Ben-Cohen Subject: Re: [PATCH V1 3/3] rpmsg: glink: Add lock for ctrl device Message-ID: References: <1643223886-28170-1-git-send-email-quic_deesin@quicinc.com> <1643223886-28170-4-git-send-email-quic_deesin@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1643223886-28170-4-git-send-email-quic_deesin@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 26 Jan 13:04 CST 2022, Deepak Kumar Singh wrote: > Race between rpmsg_eptdev_create and rpmsg_chrdev_remove > can sometime casue crash while accessing rpdev while new > endpoint is being created. Using lock ensure no new eptdev > is created after rpmsg_chrdev_remove has been completed. This patch lacks a Signed-off-by. Isn't this solving the same problem as the previous patch? Would be nice with some more specifics on the race that you're seeing. Thanks, Bjorn > --- > drivers/rpmsg/rpmsg_char.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > index 2108ef8..3e5b85d 100644 > --- a/drivers/rpmsg/rpmsg_char.c > +++ b/drivers/rpmsg/rpmsg_char.c > @@ -27,6 +27,7 @@ > > static dev_t rpmsg_major; > static struct class *rpmsg_class; > +struct mutex ctrl_lock; > > static DEFINE_IDA(rpmsg_ctrl_ida); > static DEFINE_IDA(rpmsg_ept_ida); > @@ -396,9 +397,12 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, > struct device *dev; > int ret; > > + mutex_lock(&ctrl_lock); > eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL); > - if (!eptdev) > + if (!eptdev) { > + mutex_unlock(&ctrl_lock); > return -ENOMEM; > + } > > dev = &eptdev->dev; > eptdev->rpdev = rpdev; > @@ -443,6 +447,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, > put_device(dev); > } > > + mutex_unlock(&ctrl_lock); > return ret; > > free_ept_ida: > @@ -453,6 +458,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, > put_device(dev); > kfree(eptdev); > > + mutex_unlock(&ctrl_lock); > return ret; > } > > @@ -525,6 +531,7 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) > if (!ctrldev) > return -ENOMEM; > > + mutex_init(&ctrl_lock); > ctrldev->rpdev = rpdev; > > dev = &ctrldev->dev; > @@ -581,12 +588,14 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev) > int ret; > > /* Destroy all endpoints */ > + mutex_lock(&ctrl_lock); > ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy); > if (ret) > dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret); > > device_del(&ctrldev->dev); > put_device(&ctrldev->dev); > + mutex_unlock(&ctrl_lock); > } > > static struct rpmsg_driver rpmsg_chrdev_driver = { > -- > 2.7.4 >