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[68.147.0.187]) by smtp.gmail.com with ESMTPSA id me4sm11085727pjb.26.2022.02.03.09.35.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Feb 2022 09:35:13 -0800 (PST) Date: Thu, 3 Feb 2022 10:35:10 -0700 From: Mathieu Poirier To: Deepak Kumar Singh Cc: bjorn.andersson@linaro.org, swboyd@chromium.org, quic_clew@quicinc.com, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-remoteproc@vger.kernel.org, Ohad Ben-Cohen Subject: Re: [PATCH V1 1/3] rpmsg: glink: Free device context only when cdev not in use Message-ID: <20220203173510.GA2982815@p14s> References: <1643223886-28170-1-git-send-email-quic_deesin@quicinc.com> <1643223886-28170-2-git-send-email-quic_deesin@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1643223886-28170-2-git-send-email-quic_deesin@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Deepak, On Thu, Jan 27, 2022 at 12:34:44AM +0530, Deepak Kumar Singh wrote: > Struct device holding cdev should not be freed unless cdev > is not in use. It is possible that user space has opened > char device while kernel has freed the associated struct > device context. > > Mark dev kobj as parent of cdev, so that chardev_add gets > an extra reference to dev. This ensures device context is not > freed until cdev is is not in uses. > --- > drivers/rpmsg/rpmsg_char.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > index c03a118..72ee101 100644 > --- a/drivers/rpmsg/rpmsg_char.c > +++ b/drivers/rpmsg/rpmsg_char.c > @@ -417,6 +417,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, > dev->id = ret; > dev_set_name(dev, "rpmsg%d", ret); > > + cdev_set_parent(&eptdev->cdev, &dev->kobj); > ret = cdev_add(&eptdev->cdev, dev->devt, 1); This issue should have been fixed when cdev_add() was replaced by cdev_device_add(), something you will find on v5.17-rc2. Also, this set is generating checkpatch warnings and as such I will not review the other patches in it. Thanks, Mathieu > if (ret) > goto free_ept_ida; > @@ -533,6 +534,7 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) > dev->id = ret; > dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); > > + cdev_set_parent(&ctrldev->cdev, &dev->kobj); > ret = cdev_add(&ctrldev->cdev, dev->devt, 1); > if (ret) > goto free_ctrl_ida; > -- > 2.7.4 >