Re: [PATCH v4 14/16] rpmsg: char: introduce a RPMsg driver for the RPMsg char device

From: Dan Carpenter <dan.carpenter@oracle.com>
To: kbuild@lists.01.org,
	Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Ohad Ben-Cohen <ohad@wizery.com>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Andy Gross <agross@kernel.org>
Cc: lkp@intel.com, kbuild-all@lists.01.org,
	linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-msm@vger.kernel.org, arnaud.pouliquen@foss.st.com
Subject: Re: [PATCH v4 14/16] rpmsg: char: introduce a RPMsg driver for the RPMsg char device
Date: Thu, 18 Feb 2021 15:33:34 +0300	[thread overview]
Message-ID: <20210218123333.GK2087@kadam> (raw)
In-Reply-To: <20210217132905.1485-15-arnaud.pouliquen@foss.st.com>

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Hi Arnaud,

url:    https://github.com/0day-ci/linux/commits/Arnaud-Pouliquen/introduce-a-generic-IOCTL-interface-for-RPMsg-channels-management/20210217-214044
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git f40ddce88593482919761f74910f42f4b84c004b
config: riscv-randconfig-m031-20210215 (attached as .config)
compiler: riscv32-linux-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/rpmsg/rpmsg_char.c:429 rpmsg_chrdev_probe() error: we previously assumed 'rpdev->ept' could be null (see line 423)

vim +429 drivers/rpmsg/rpmsg_char.c

7337f30f7a4426 Arnaud Pouliquen 2021-02-17  413  static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  414  {
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  415  	struct rpmsg_channel_info chinfo;
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  416  	struct rpmsg_eptdev *eptdev;
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  417  
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  418  	memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME));
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  419  	chinfo.src = rpdev->src;
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  420  	chinfo.dst = rpdev->dst;
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  421  
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  422  	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, &rpdev->dev, chinfo);
7337f30f7a4426 Arnaud Pouliquen 2021-02-17 @423  	if (IS_ERR(eptdev) && rpdev->ept) {
                                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This condition is strange.

7337f30f7a4426 Arnaud Pouliquen 2021-02-17  424  		rpmsg_destroy_ept(rpdev->ept);
                                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
What?  Why are we undoing this when it's not something that we created?
This seems like a layering violation...

7337f30f7a4426 Arnaud Pouliquen 2021-02-17  425  		return PTR_ERR(eptdev);
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  426  	}
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  427  
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  428  	/* Set the private field of the default endpoint to retrieve context on callback. */
7337f30f7a4426 Arnaud Pouliquen 2021-02-17 @429  	rpdev->ept->priv = eptdev;
                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^
If "rpdev->ept" is NULL this will Oops.  If "eptdev" is an error pointer
that seems wrong as well.

7337f30f7a4426 Arnaud Pouliquen 2021-02-17  430  
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  431  	return 0;
7337f30f7a4426 Arnaud Pouliquen 2021-02-17  432  }

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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