void shrink_dcache_sb(struct super_block *sb)
{
	long freed;

	do {
		LIST_HEAD(dispose);

		freed = list_lru_walk(&sb->s_dentry_lru,
			dentry_lru_isolate_shrink, &dispose, UINT_MAX);

		this_cpu_sub(nr_dentry_unused, freed);
		shrink_dentry_list(&dispose);
	} while (freed > 0);
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.