On Thu, Aug 12, 2021 at 01:26:02AM +0800, kernel test robot wrote:

Hi Naohiro,

I love your patch! Perhaps something to improve:

[auto build test WARNING on kdave/for-next]
[cannot apply to v5.14-rc5 next-20210811]
[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]

url:    https://github.com/0day-ci/linux/commits/Naohiro-Aota/ZNS-Support-for-Btrfs/20210811-222302
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
config: hexagon-randconfig-r041-20210810 (attached as .config)
compiler: clang version 12.0.0
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/0day-ci/linux/commit/ccecd271dc2436fe587af8d2083c3c96ab86e309
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Naohiro-Aota/ZNS-Support-for-Btrfs/20210811-222302
        git checkout ccecd271dc2436fe587af8d2083c3c96ab86e309
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=hexagon 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All warnings (new ones prefixed by >>):

quoted

quoted

fs/btrfs/zoned.c:1948:2: warning: variable 'ret' is used uninitialized whenever '?:' condition is true [-Wsometimes-uninitialized]

           ASSERT(!list_empty(&block_group->active_bg_list));
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/btrfs/ctree.h:3458:3: note: expanded from macro 'ASSERT'
           (likely(expr) ? (void)0 : assertfail(#expr, __FILE__, __LINE__))
            ^~~~~~~~~~~~
   include/linux/compiler.h:77:20: note: expanded from macro 'likely'
   # define likely(x)      __builtin_expect(!!(x), 1)
                           ^~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/btrfs/zoned.c:1956:9: note: uninitialized use occurs here
           return ret;
                  ^~~
   fs/btrfs/zoned.c:1948:2: note: remove the '?:' if its condition is always false
           ASSERT(!list_empty(&block_group->active_bg_list));
           ^
   fs/btrfs/ctree.h:3458:3: note: expanded from macro 'ASSERT'
           (likely(expr) ? (void)0 : assertfail(#expr, __FILE__, __LINE__))
            ^
   include/linux/compiler.h:77:20: note: expanded from macro 'likely'
   # define likely(x)      __builtin_expect(!!(x), 1)
                           ^
   fs/btrfs/zoned.c:1908:9: note: initialize the variable 'ret' to silence this warning
           int ret;
                  ^
                   = 0
   1 warning generated.

This looks false-positive for me but still I noticed this "ret" can
never be non-zero in any path. So, I'll convert the function to "void"
in the next version.