[brauner-vfs:work.pidfs.thread_group 4/8] fs/pidfs.c:213:14: warning: unused variable 'thread'

[brauner-vfs:work.pidfs.thread_group 4/8] fs/pidfs.c:213:14: warning: unused variable 'thread'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git work.pidfs.thread_group
head:   d0a0cf0bc25c919225b65ae639aaeb05747974a3
commit: 65d0a567a7317093032cfd56cae7aa7417b03d17 [4/8] pidfs: improve multi-threaded exec and premature thread-group leader exit polling
config: i386-buildonly-randconfig-001-20250320 (https://download.01.org/0day-ci/archive/20250320/202503202312.SmfIIwCj-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250320/202503202312.SmfIIwCj-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/202503202312.SmfIIwCj-lkp@intel.com/

All warnings (new ones prefixed by >>):

   fs/pidfs.c: In function 'pidfd_poll':
>> fs/pidfs.c:213:14: warning: unused variable 'thread' [-Wunused-variable]
     213 |         bool thread = file->f_flags & PIDFD_THREAD;
         |              ^~~~~~


vim +/thread +213 fs/pidfs.c

50f4f2d197e194 Christian Brauner 2024-02-12  206  
50f4f2d197e194 Christian Brauner 2024-02-12  207  /*
50f4f2d197e194 Christian Brauner 2024-02-12  208   * Poll support for process exit notification.
50f4f2d197e194 Christian Brauner 2024-02-12  209   */
50f4f2d197e194 Christian Brauner 2024-02-12  210  static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts)
50f4f2d197e194 Christian Brauner 2024-02-12  211  {
cb12fd8e0dabb9 Christian Brauner 2024-02-12  212  	struct pid *pid = pidfd_pid(file);
50f4f2d197e194 Christian Brauner 2024-02-12 @213  	bool thread = file->f_flags & PIDFD_THREAD;
50f4f2d197e194 Christian Brauner 2024-02-12  214  	struct task_struct *task;
50f4f2d197e194 Christian Brauner 2024-02-12  215  	__poll_t poll_flags = 0;
50f4f2d197e194 Christian Brauner 2024-02-12  216  
50f4f2d197e194 Christian Brauner 2024-02-12  217  	poll_wait(file, &pid->wait_pidfd, pts);
50f4f2d197e194 Christian Brauner 2024-02-12  218  	/*
50f4f2d197e194 Christian Brauner 2024-02-12  219  	 * Depending on PIDFD_THREAD, inform pollers when the thread
50f4f2d197e194 Christian Brauner 2024-02-12  220  	 * or the whole thread-group exits.
65d0a567a73170 Christian Brauner 2025-03-19  221  	 *
65d0a567a73170 Christian Brauner 2025-03-19  222  	 * There are two corner cases to consider:
65d0a567a73170 Christian Brauner 2025-03-19  223  	 *
65d0a567a73170 Christian Brauner 2025-03-19  224  	 * (1) If a thread-group leader of a thread-group with
65d0a567a73170 Christian Brauner 2025-03-19  225  	 *     subthreads exits prematurely, i.e., before all of the
65d0a567a73170 Christian Brauner 2025-03-19  226  	 *     subthreads of the thread-group have exited then no
65d0a567a73170 Christian Brauner 2025-03-19  227  	 *     notification will be generated for PIDFD_THREAD pidfds
65d0a567a73170 Christian Brauner 2025-03-19  228  	 *     referring to the thread-group leader.
65d0a567a73170 Christian Brauner 2025-03-19  229  	 *
65d0a567a73170 Christian Brauner 2025-03-19  230  	 *     The exit notification for the thread-group leader will be
65d0a567a73170 Christian Brauner 2025-03-19  231  	 *     delayed until the last subthread of the thread-group
65d0a567a73170 Christian Brauner 2025-03-19  232  	 *     exits.
65d0a567a73170 Christian Brauner 2025-03-19  233  	 *
65d0a567a73170 Christian Brauner 2025-03-19  234  	 * (2) If a subthread of a thread-group execs then the
65d0a567a73170 Christian Brauner 2025-03-19  235  	 *     current thread-group leader will be SIGKILLed and the
65d0a567a73170 Christian Brauner 2025-03-19  236  	 *     subthread will assume the struct pid of the now defunct
65d0a567a73170 Christian Brauner 2025-03-19  237  	 *     old thread-group leader. No exit notification will be
65d0a567a73170 Christian Brauner 2025-03-19  238  	 *     generated for PIDFD_THREAD pidfds referring to the old
65d0a567a73170 Christian Brauner 2025-03-19  239  	 *     thread-group leader as they continue referring to the new
65d0a567a73170 Christian Brauner 2025-03-19  240  	 *     thread-group leader.
50f4f2d197e194 Christian Brauner 2024-02-12  241  	 */
50f4f2d197e194 Christian Brauner 2024-02-12  242  	guard(rcu)();
50f4f2d197e194 Christian Brauner 2024-02-12  243  	task = pid_task(pid, PIDTYPE_PID);
50f4f2d197e194 Christian Brauner 2024-02-12  244  	if (!task)
50f4f2d197e194 Christian Brauner 2024-02-12  245  		poll_flags = EPOLLIN | EPOLLRDNORM | EPOLLHUP;
65d0a567a73170 Christian Brauner 2025-03-19  246  	else if (task->exit_state && !delay_group_leader(task))
50f4f2d197e194 Christian Brauner 2024-02-12  247  		poll_flags = EPOLLIN | EPOLLRDNORM;
50f4f2d197e194 Christian Brauner 2024-02-12  248  
50f4f2d197e194 Christian Brauner 2024-02-12  249  	return poll_flags;
50f4f2d197e194 Christian Brauner 2024-02-12  250  }
50f4f2d197e194 Christian Brauner 2024-02-12  251  

:::::: The code at line 213 was first introduced by commit
:::::: 50f4f2d197e194ec0356962b99ca2b72e9a37bc8 pidfd: move struct pidfd_fops

:::::: TO: Christian Brauner <brauner@kernel.org>
:::::: CC: Christian Brauner <brauner@kernel.org>

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