eventfs: Initialize ei->children and ei->list in init_ei()

Summary

In the Linux kernel, the following vulnerability has been resolved:

eventfs: Initialize ei->children and ei->list in init_ei()

eventfs_create_dir() allocates the eventfs_inode and initializes it with init_ei(). But this does not initialize the eventfs_inode list_heads. If the eventfs_create_dir() fails due to memory pressure, it will call free_ei() before it initialized the lists, and that checks to make sure the eventfs_inode has no children. But because the list wasn't initialized, it will give a false warning.

Fix it by moving the list initialization into init_ei().

[ Rewrote change log ]