Hi Yoochan,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on soc/for-next]
[also build test ERROR on char-misc/char-misc-testing char-misc/char-misc-next char-misc/char-misc-linus linus/master v6.2-rc1 next-20221226]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Yoochan-Lee/char-xilinx_hwicap-xilinx_hwicap-Fix-use-after-free-in-hwicap_open/20221231-112957
base:   https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
patch link:    https://lore.kernel.org/r/20221231032826.2034288-1-yoochan1026%40gmail.com
patch subject: [PATCH] char: xilinx_hwicap: xilinx_hwicap: Fix use-after-free in hwicap_open
config: microblaze-randconfig-r013-20221226
compiler: microblaze-linux-gcc (GCC) 12.1.0
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://github.com/intel-lab-lkp/linux/commit/85568c4b21398a7da51b017dbbf78424b59f1f2f
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Yoochan-Lee/char-xilinx_hwicap-xilinx_hwicap-Fix-use-after-free-in-hwicap_open/20221231-112957
        git checkout 85568c4b21398a7da51b017dbbf78424b59f1f2f
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=microblaze olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=microblaze SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/char/xilinx_hwicap/xilinx_hwicap.c: In function 'hwicap_release':
>> drivers/char/xilinx_hwicap/xilinx_hwicap.c:587:36: error: 'hwicap_delete' undeclared (first use in this function); did you mean 'hwicap_release'?
     587 |         kref_put(&drvdata->refcnt, hwicap_delete);
         |                                    ^~~~~~~~~~~~~
         |                                    hwicap_release
   drivers/char/xilinx_hwicap/xilinx_hwicap.c:587:36: note: each undeclared identifier is reported only once for each function it appears in
   drivers/char/xilinx_hwicap/xilinx_hwicap.c: In function 'hwicap_remove':
   drivers/char/xilinx_hwicap/xilinx_hwicap.c:736:36: error: 'hwicap_delete' undeclared (first use in this function); did you mean 'hwicap_release'?
     736 |         kref_put(&drvdata->refcnt, hwicap_delete);
         |                                    ^~~~~~~~~~~~~
         |                                    hwicap_release
   In file included from include/linux/fs.h:7,
                    from include/linux/huge_mm.h:8,
                    from include/linux/mm.h:737,
                    from arch/microblaze/include/asm/io.h:14,
                    from include/linux/io.h:13,
                    from include/linux/irq.h:20,
                    from include/asm-generic/hardirq.h:17,
                    from ./arch/microblaze/include/generated/asm/hardirq.h:1,
                    from include/linux/hardirq.h:11,
                    from include/linux/interrupt.h:11,
                    from drivers/char/xilinx_hwicap/xilinx_hwicap.c:78:
   drivers/char/xilinx_hwicap/xilinx_hwicap.c: In function 'hwicap_delete':
>> drivers/char/xilinx_hwicap/xilinx_hwicap.c:840:30: error: 'dev' undeclared (first use in this function); did you mean 'cdev'?
     840 |         probed_devices[MINOR(dev->devt)-XHWICAP_MINOR] = 0;
         |                              ^~~
   include/linux/kdev_t.h:11:43: note: in definition of macro 'MINOR'
      11 | #define MINOR(dev)      ((unsigned int) ((dev) & MINORMASK))
         |                                           ^~~
   drivers/char/xilinx_hwicap/xilinx_hwicap.c: At top level:
   drivers/char/xilinx_hwicap/xilinx_hwicap.c:829:13: warning: 'hwicap_delete' defined but not used [-Wunused-function]
     829 | static void hwicap_delete(struct kref *kref)
         |             ^~~~~~~~~~~~~


vim +587 drivers/char/xilinx_hwicap/xilinx_hwicap.c

   564	
   565	static int hwicap_release(struct inode *inode, struct file *file)
   566	{
   567		struct hwicap_drvdata *drvdata = file->private_data;
   568		int i;
   569		int status = 0;
   570	
   571		mutex_lock(&drvdata->sem);
   572	
   573		if (drvdata->write_buffer_in_use) {
   574			/* Flush write buffer. */
   575			for (i = drvdata->write_buffer_in_use; i < 4; i++)
   576				drvdata->write_buffer[i] = 0;
   577	
   578			status = drvdata->config->set_configuration(drvdata,
   579					(u32 *) drvdata->write_buffer, 1);
   580			if (status)
   581				goto error;
   582		}
   583	
   584		status = hwicap_command_desync(drvdata);
   585		if (status)
   586			goto error;
 > 587		kref_put(&drvdata->refcnt, hwicap_delete);
   588	
   589	 error:
   590		drvdata->is_open = 0;
   591		mutex_unlock(&drvdata->sem);
   592		return status;
   593	}
   594	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp