BTW, looking through the code related to struct net lifetime rules has
caught something else:
struct net *get_net_ns_by_fd(int fd)
{
...
file = proc_ns_fget(fd);
if (!file)
goto out;
ei = PROC_I(file->f_dentry->d_inode);
while in proc_ns_fget() we have two return ERR_PTR(...) and not a single
path that would return NULL. The other caller of proc_ns_fget() treats
ERR_PTR() correctly...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
c316e6a308