Re: [PATCH] net/mac80211: replace scnprintf() with sysfs_emit() for sysfs output

[kernel test robot <lkp@intel.com>]

Hi Mande,

kernel test robot noticed the following build warnings:

[auto build test WARNING on wireless-next/main]
[also build test WARNING on wireless/main linus/master v6.16 next-20250731]
[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/Mande-Imran-Ahmed/net-mac80211-replace-scnprintf-with-sysfs_emit-for-sysfs-output/20250730-180128
base:   https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next.git main
patch link:    https://lore.kernel.org/r/20250730095634.3754-1-immu.ahmed1905%40gmail.com
patch subject: [PATCH] net/mac80211: replace scnprintf() with sysfs_emit() for sysfs output
config: powerpc-randconfig-001-20250801 (https://download.01.org/0day-ci/archive/20250801/202508011121.dDTSwRyY-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 13.4.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250801/202508011121.dDTSwRyY-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202508011121.dDTSwRyY-lkp@intel.com/

All warnings (new ones prefixed by >>):

   net/mac80211/debugfs_sta.c: In function 'sta_flags_read':
>> net/mac80211/debugfs_sta.c:99:16: warning: 'buf' is used uninitialized [-Wuninitialized]
      99 |         return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
         |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from include/linux/string.h:65,
                    from include/linux/bitmap.h:13,
                    from include/linux/cpumask.h:12,
                    from include/linux/smp.h:13,
                    from include/linux/lockdep.h:14,
                    from include/linux/spinlock.h:63,
                    from include/linux/wait.h:9,
                    from include/linux/wait_bit.h:8,
                    from include/linux/fs.h:7,
                    from include/linux/debugfs.h:15,
                    from net/mac80211/debugfs_sta.c:11:
   arch/powerpc/include/asm/string.h:22:24: note: by argument 1 of type 'const char *' to 'strlen' declared here
      22 | extern __kernel_size_t strlen(const char *);
         |                        ^~~~~~
   net/mac80211/debugfs_sta.c:87:14: note: 'buf' declared here
      87 |         char buf[16 * NUM_WLAN_STA_FLAGS], *pos = buf;
         |              ^~~


vim +/buf +99 net/mac80211/debugfs_sta.c

c84387d2f2c83d Johannes Berg     2016-03-17   83  
e9f207f0ff90bf Jiri Benc         2007-05-05   84  static ssize_t sta_flags_read(struct file *file, char __user *userbuf,
e9f207f0ff90bf Jiri Benc         2007-05-05   85  			      size_t count, loff_t *ppos)
e9f207f0ff90bf Jiri Benc         2007-05-05   86  {
c84387d2f2c83d Johannes Berg     2016-03-17   87  	char buf[16 * NUM_WLAN_STA_FLAGS], *pos = buf;
e9f207f0ff90bf Jiri Benc         2007-05-05   88  	struct sta_info *sta = file->private_data;
c84387d2f2c83d Johannes Berg     2016-03-17   89  	unsigned int flg;
c84387d2f2c83d Johannes Berg     2016-03-17   90  
c84387d2f2c83d Johannes Berg     2016-03-17   91  	BUILD_BUG_ON(ARRAY_SIZE(sta_flag_names) != NUM_WLAN_STA_FLAGS);
c2c98fdeb5c897 Johannes Berg     2011-09-29   92  
c84387d2f2c83d Johannes Berg     2016-03-17   93  	for (flg = 0; flg < NUM_WLAN_STA_FLAGS; flg++) {
c84387d2f2c83d Johannes Berg     2016-03-17   94  		if (test_sta_flag(sta, flg))
ec95570844b7a6 Mande Imran Ahmed 2025-07-30   95  			pos += sysfs_emit(pos, "%s\n",
c84387d2f2c83d Johannes Berg     2016-03-17   96  					 sta_flag_names[flg]);
c84387d2f2c83d Johannes Berg     2016-03-17   97  	}
5bade101eceedb Johannes Berg     2011-09-29   98  
c84387d2f2c83d Johannes Berg     2016-03-17  @99  	return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
e9f207f0ff90bf Jiri Benc         2007-05-05  100  }
e9f207f0ff90bf Jiri Benc         2007-05-05  101  STA_OPS(flags);
e9f207f0ff90bf Jiri Benc         2007-05-05  102  

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