On Thu, Jun 07, 2018 at 01:39:49PM -0700, Cong Wang wrote: > fchownat() doesn't even hold refcnt of fd until it figures out > fd is really needed (otherwise is ignored) and releases it after > it resolves the path. This means sock_close() could race with > sockfs_setattr(), which leads to a NULL pointer dereference > since typically we set sock->sk to NULL in ->release(). > > As pointed out by Al, this is unique to sockfs. So we can fix this > in socket layer by acquiring inode_lock in sock_close() and > checking against NULL in sockfs_setattr().
That looks like a massive overkill - it's way heavier than it should be. And it's very likely to trigger shitloads of deadlock warnings, some possibly even true.
