rxrpc_call structs don't pin sockets or network namespaces, but may attempt
to access both after their refcount reaches 0 so that they can detach
themselves from the network namespace. However, there's no guarantee that
the socket still exists at this point (so sock_net(&call->socket->sk) may
be invalid) and the namespace may have gone away if the call isn't pinning
a peer.
Fix this by (a) carrying a net pointer in the rxrpc_call struct and (b)
waiting for all calls to be destroyed when the network namespace goes away.
This was detected by checker:
net/rxrpc/call_object.c:634:57: warning: incorrect type in argument 1 (different address spaces)
net/rxrpc/call_object.c:634:57: expected struct sock const *sk
net/rxrpc/call_object.c:634:57: got struct sock [noderef] <asn:4>*<noident>
Fixes: 2baec2c3f8 ("rxrpc: Support network namespacing")
Signed-off-by: David Howells <dhowells@redhat.com>
d3be4d2443