Code: void put_filp(struct file *file)
 {
 	if (atomic_long_dec_and_test(&file->f_count)) {
 		security_file_free(file);
		file_sb_list_del(file);
 		file_free(file);
 	}
 }

Vulnerability Type: DoS 
CWE ID: CWE-17
Summary: The filesystem implementation in the Linux kernel before 3.13 performs certain operations on lists of files with an inappropriate locking approach, which allows local users to cause a denial of service (soft lockup or system crash) via unspecified use of Asynchronous I/O (AIO) operations.
Commit Message: get rid of s_files and files_lock

The only thing we need it for is alt-sysrq-r (emergency remount r/o)
and these days we can do just as well without going through the
list of files.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>