Hi "Eric,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on bpf/master]
[also build test WARNING on linus/master v5.9-rc1 next-20200817]
[cannot apply to bpf-next/master linux/master]
[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/Eric-W-Biederman/exec-Move-unshare_files-to-fix-posix-file-locking-during-exec/20200818-061552
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master
config: i386-randconfig-m021-20200818 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0

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

smatch warnings:
kernel/bpf/task_iter.c:162 task_file_seq_get_next() warn: ignoring unreachable 
code.

# 
https://github.com/0day-ci/linux/commit/66f80aa453b17f8932b42e18265dba5fdb32490e
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review 
Eric-W-Biederman/exec-Move-unshare_files-to-fix-posix-file-locking-during-exec/20200818-061552
git checkout 66f80aa453b17f8932b42e18265dba5fdb32490e
vim +162 kernel/bpf/task_iter.c

   128  
   129  static struct file *
   130  task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info,
   131                         struct task_struct **task)
   132  {
   133          struct pid_namespace *ns = info->common.ns;
   134          u32 curr_tid = info->tid;
   135          struct task_struct *curr_task;
   136          unsigned int curr_fd = info->fd;
   137  
   138          /* If this function returns a non-NULL file object,
   139           * it held a reference to the task/file.
   140           * Otherwise, it does not hold any reference.
   141           */
   142  again:
   143          if (*task) {
   144                  curr_task = *task;
   145                  curr_fd = info->fd;
   146          } else {
   147                  curr_task = task_seq_get_next(ns, &curr_tid);
   148                  if (!curr_task)
   149                          return NULL;
   150  
   151                  /* set *task and info->tid */
   152                  *task = curr_task;
   153                  if (curr_tid == info->tid) {
   154                          curr_fd = info->fd;
   155                  } else {
   156                          info->tid = curr_tid;
   157                          curr_fd = 0;
   158                  }
   159          }
   160  
   161          rcu_read_lock();
 > 162          for (;; curr_fd++) {
   163                  struct file *f;
   164  
   165                  f = fnext_task(curr_task, &curr_fd);
   166                  if (!f)
   167                          break;
   168  
   169                  /* set info->fd */
   170                  info->fd = curr_fd;
   171                  get_file(f);
   172                  rcu_read_unlock();
   173                  return f;
   174          }
   175  
   176          /* the current task is done, go to the next task */
   177          rcu_read_unlock();
   178          put_task_struct(curr_task);
   179          *task = NULL;
   180          info->fd = 0;
   181          curr_tid = ++(info->tid);
   182          goto again;
   183  }
   184  

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

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