linux-kernel - [cxl-cxl:pending 31/38] drivers/cxl/pmem.c:66:6: warning: variable 'nvdimm' is used uninitialized whenever 'if' condition is true

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Message-ID: <202108141400.cUDQV9sC-lkp@intel.com>
Date:   Sat, 14 Aug 2021 14:58:10 +0800
From:   kernel test robot <lkp@...el.com>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     clang-built-linux@...glegroups.com, kbuild-all@...ts.01.org,
        Alison Schofield <alison.schofield@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Ben Widawsky <ben.widawsky@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        linux-kernel@...r.kernel.org
Subject: [cxl-cxl:pending 31/38] drivers/cxl/pmem.c:66:6: warning: variable
 'nvdimm' is used uninitialized whenever 'if' condition is true

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git pending
head:   fa809cc6feedcd2575b63def7135dfaf066266bb
commit: fc6fd550b9f1ada1bdb5e12f83e3794e81a2eb42 [31/38] cxl/mbox: Add exclusive kernel command support
config: x86_64-randconfig-a015-20210814 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 1f7b25ea76a925aca690da28de9d78db7ca99d0c)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git/commit/?id=fc6fd550b9f1ada1bdb5e12f83e3794e81a2eb42
        git remote add cxl-cxl https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git
        git fetch --no-tags cxl-cxl pending
        git checkout fc6fd550b9f1ada1bdb5e12f83e3794e81a2eb42
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>

All warnings (new ones prefixed by >>):

>> drivers/cxl/pmem.c:66:6: warning: variable 'nvdimm' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (!cxl_nvb->nvdimm_bus)
               ^~~~~~~~~~~~~~~~~~~~
   drivers/cxl/pmem.c:80:7: note: uninitialized use occurs here
           if (!nvdimm && rc == 0)
                ^~~~~~
   drivers/cxl/pmem.c:66:2: note: remove the 'if' if its condition is always false
           if (!cxl_nvb->nvdimm_bus)
           ^~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/cxl/pmem.c:58:23: note: initialize the variable 'nvdimm' to silence this warning
           struct nvdimm *nvdimm;
                                ^
                                 = NULL
   1 warning generated.


vim +66 drivers/cxl/pmem.c

21083f51521fb0 Dan Williams 2021-06-15  50  
21083f51521fb0 Dan Williams 2021-06-15  51  static int cxl_nvdimm_probe(struct device *dev)
21083f51521fb0 Dan Williams 2021-06-15  52  {
21083f51521fb0 Dan Williams 2021-06-15  53  	struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
fc6fd550b9f1ad Dan Williams 2021-06-17  54  	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
fc6fd550b9f1ad Dan Williams 2021-06-17  55  	struct cxl_mem *cxlm = cxlmd->cxlm;
21083f51521fb0 Dan Williams 2021-06-15  56  	struct cxl_nvdimm_bridge *cxl_nvb;
21083f51521fb0 Dan Williams 2021-06-15  57  	unsigned long flags = 0;
21083f51521fb0 Dan Williams 2021-06-15  58  	struct nvdimm *nvdimm;
21083f51521fb0 Dan Williams 2021-06-15  59  	int rc = -ENXIO;
21083f51521fb0 Dan Williams 2021-06-15  60  
21083f51521fb0 Dan Williams 2021-06-15  61  	cxl_nvb = cxl_find_nvdimm_bridge();
21083f51521fb0 Dan Williams 2021-06-15  62  	if (!cxl_nvb)
21083f51521fb0 Dan Williams 2021-06-15  63  		return -ENXIO;
21083f51521fb0 Dan Williams 2021-06-15  64  
21083f51521fb0 Dan Williams 2021-06-15  65  	device_lock(&cxl_nvb->dev);
21083f51521fb0 Dan Williams 2021-06-15 @66  	if (!cxl_nvb->nvdimm_bus)
21083f51521fb0 Dan Williams 2021-06-15  67  		goto out;
21083f51521fb0 Dan Williams 2021-06-15  68  
fc6fd550b9f1ad Dan Williams 2021-06-17  69  	set_exclusive_cxl_commands(cxlm, exclusive_cmds);
fc6fd550b9f1ad Dan Williams 2021-06-17  70  
21083f51521fb0 Dan Williams 2021-06-15  71  	set_bit(NDD_LABELING, &flags);
21083f51521fb0 Dan Williams 2021-06-15  72  	nvdimm = nvdimm_create(cxl_nvb->nvdimm_bus, cxl_nvd, NULL, flags, 0, 0,
21083f51521fb0 Dan Williams 2021-06-15  73  			       NULL);
fc6fd550b9f1ad Dan Williams 2021-06-17  74  	dev_set_drvdata(dev, nvdimm);
fc6fd550b9f1ad Dan Williams 2021-06-17  75  	rc = devm_add_action_or_reset(dev, unregister_nvdimm, cxl_nvd);
21083f51521fb0 Dan Williams 2021-06-15  76  out:
21083f51521fb0 Dan Williams 2021-06-15  77  	device_unlock(&cxl_nvb->dev);
21083f51521fb0 Dan Williams 2021-06-15  78  	put_device(&cxl_nvb->dev);
21083f51521fb0 Dan Williams 2021-06-15  79  
fc6fd550b9f1ad Dan Williams 2021-06-17  80  	if (!nvdimm && rc == 0)
fc6fd550b9f1ad Dan Williams 2021-06-17  81  		rc = -ENOMEM;
fc6fd550b9f1ad Dan Williams 2021-06-17  82  
21083f51521fb0 Dan Williams 2021-06-15  83  	return rc;
21083f51521fb0 Dan Williams 2021-06-15  84  }
21083f51521fb0 Dan Williams 2021-06-15  85  

:::::: The code at line 66 was first introduced by commit
:::::: 21083f51521fb0f60dbac591f175c3ed48435af4 cxl/pmem: Register 'pmem' / cxl_nvdimm devices

:::::: TO: Dan Williams <dan.j.williams@...el.com>
:::::: CC: Dan Williams <dan.j.williams@...el.com>

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

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