[android-common:android13-5.15-lts 2/2] fs/eventpoll.c:1009:2-11: second lock on line 994

[android-common:android13-5.15-lts 2/2] fs/eventpoll.c:1009:2-11: second lock on line 994

[kernel test robot]

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: cros-kernel-buildreports@googlegroups.com

tree:   https://android.googlesource.com/kernel/common android13-5.15-lts
head:   28ca5d8b733ed5c4ea847e57cc94f90cfa929e94
commit: 9208957e850335d35905a45e0041c09aac9ea5fb [2/2] UPSTREAM: eventpoll: kill __ep_remove()
:::::: branch date: 10 hours ago
:::::: commit date: 6 days ago
config: x86_64-randconfig-2102-20261025 (https://download.01.org/0day-ci/archive/20261025/202610252137.KYEUgiaP-lkp@intel.com/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project a808f8ea7fdc61ead417bfe55e8ef5f728776aeb)

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>
| Reported-by: Julia Lawall <julia.lawall@inria.fr>
| Closes: https://lore.kernel.org/r/202610252137.KYEUgiaP-lkp@intel.com/

cocci warnings: (new ones prefixed by >>)
>> fs/eventpoll.c:1009:2-11: second lock on line 994

vim +1009 fs/eventpoll.c

7699acd1341c63 Davide Libenzi    2007-05-10   976  
b611967de4dc5c Davide Libenzi    2006-10-11   977  /*
7699acd1341c63 Davide Libenzi    2007-05-10   978   * This is called from eventpoll_release() to unlink files from the eventpoll
7699acd1341c63 Davide Libenzi    2007-05-10   979   * interface. We need to have this facility to cleanup correctly files that are
7699acd1341c63 Davide Libenzi    2007-05-10   980   * closed without being removed from the eventpoll interface.
b611967de4dc5c Davide Libenzi    2006-10-11   981   */
7699acd1341c63 Davide Libenzi    2007-05-10   982  void eventpoll_release_file(struct file *file)
b611967de4dc5c Davide Libenzi    2006-10-11   983  {
7699acd1341c63 Davide Libenzi    2007-05-10   984  	struct eventpoll *ep;
44cdc1d952e3f7 Al Viro           2020-09-27   985  	struct epitem *epi;
f2451def095c17 Paolo Abeni       2023-03-22   986  	bool dispose;
f2451def095c17 Paolo Abeni       2023-03-22   987  
f2451def095c17 Paolo Abeni       2023-03-22   988  	/*
f2451def095c17 Paolo Abeni       2023-03-22   989  	 * Use the 'dying' flag to prevent a concurrent ep_clear_and_put() from
f2451def095c17 Paolo Abeni       2023-03-22   990  	 * touching the epitems list before eventpoll_release_file() can access
f2451def095c17 Paolo Abeni       2023-03-22   991  	 * the ep->mtx.
f2451def095c17 Paolo Abeni       2023-03-22   992  	 */
f2451def095c17 Paolo Abeni       2023-03-22   993  again:
f2451def095c17 Paolo Abeni       2023-03-22  @994  	spin_lock(&file->f_lock);
f2451def095c17 Paolo Abeni       2023-03-22   995  	if (file->f_ep && file->f_ep->first) {
f2451def095c17 Paolo Abeni       2023-03-22   996  		epi = hlist_entry(file->f_ep->first, struct epitem, fllink);
9208957e850335 Christian Brauner 2026-09-29   997  		WRITE_ONCE(epi->dying, true);
f2451def095c17 Paolo Abeni       2023-03-22   998  		spin_unlock(&file->f_lock);
f2451def095c17 Paolo Abeni       2023-03-22   999  
f2451def095c17 Paolo Abeni       2023-03-22  1000  		/*
f2451def095c17 Paolo Abeni       2023-03-22  1001  		 * ep access is safe as we still own a reference to the ep
f2451def095c17 Paolo Abeni       2023-03-22  1002  		 * struct
b611967de4dc5c Davide Libenzi    2006-10-11  1003  		 */
7699acd1341c63 Davide Libenzi    2007-05-10  1004  		ep = epi->ep;
f2451def095c17 Paolo Abeni       2023-03-22  1005  		mutex_lock(&ep->mtx);
9208957e850335 Christian Brauner 2026-09-29  1006  
9208957e850335 Christian Brauner 2026-09-29  1007  		ep_unregister_pollwait(ep, epi);
9208957e850335 Christian Brauner 2026-09-29  1008  
9208957e850335 Christian Brauner 2026-09-29 @1009  		spin_lock(&file->f_lock);
9208957e850335 Christian Brauner 2026-09-29  1010  		__ep_remove_file(ep, epi, file);
9208957e850335 Christian Brauner 2026-09-29  1011  		dispose = __ep_remove_epi(ep, epi);
9208957e850335 Christian Brauner 2026-09-29  1012  
d47de16c722196 Davide Libenzi    2007-05-15  1013  		mutex_unlock(&ep->mtx);
f2451def095c17 Paolo Abeni       2023-03-22  1014  
c36fff461c90c6 Linus Torvalds    2025-07-09  1015  		if (dispose && ep_refcount_dec_and_test(ep))
f2451def095c17 Paolo Abeni       2023-03-22  1016  			ep_free(ep);
f2451def095c17 Paolo Abeni       2023-03-22  1017  		goto again;
b611967de4dc5c Davide Libenzi    2006-10-11  1018  	}
f2451def095c17 Paolo Abeni       2023-03-22  1019  	spin_unlock(&file->f_lock);
b611967de4dc5c Davide Libenzi    2006-10-11  1020  }
b611967de4dc5c Davide Libenzi    2006-10-11  1021  

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