mmap/MAP_SHARED and mandatory flock

It seems to me that the mmap/MAP_SHARED locks_verify_locked() check and fcntl_setlk() have no synchronization. For example, a process invoking fcntl_setlk on a IS_MANDLOCK inode can check that it has no i_mmap vma list, then go on and sleep later before queueing a file_lock on the inode i_flock. Subsequently, an mmaper can come in, invoke locks_verify_locked(), see no file_lock on the inode i_flock, and succeed. The file locker can then wake up and also return success.

Am I missing some synchronization lock/algorithm?

Kanoj
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