RDMA/rxe: let rxe_reclassify_recv_socket() call sk_owner_put()

On kernels build with CONFIG_PROVE_LOCKING, CONFIG_MODULES
and CONFIG_DEBUG_LOCK_ALLOC 'rmmod rdma_rxe' is no longer
possible.

For the global recv sockets rxe_net_exit() is where we
call rxe_release_udp_tunnel-> udp_tunnel_sock_release(),
which means the sockets are destroyed before 'rmmod rdma_rxe'
finishes, so there's no need to protect against
rxe_recv_slock_key and rxe_recv_sk_key disappearing
while the sockets are still alive.

Fixes: 80a85a771deb ("RDMA/rxe: reclassify sockets in order to avoid false positives from lockdep")
Cc: Zhu Yanjun <zyjzyj2000@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Cc: linux-rdma@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Link: https://patch.msgid.link/20251219140408.2300163-1-metze@samba.org
Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
index 0195d361e5e3582b6eff88f31ec925640280e4c6..0bd0902b11f734acbbb9fa521bf117bbf6a7710d 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -64,7 +64,39 @@ static inline void rxe_reclassify_recv_socket(struct socket *sock)
                break;
        default:
                WARN_ON_ONCE(1);
+               return;
        }
+       /*
+        * sock_lock_init_class_and_name() calls
+        * sk_owner_set(sk, THIS_MODULE); in order
+        * to make sure the referenced global
+        * variables rxe_recv_slock_key and
+        * rxe_recv_sk_key are not removed
+        * before the socket is closed.
+        *
+        * However this prevents rxe_net_exit()
+        * from being called and 'rmmod rdma_rxe'
+        * is refused because of the references.
+        *
+        * For the global sockets in recv_sockets,
+        * we are sure that rxe_net_exit() will call
+        * rxe_release_udp_tunnel -> udp_tunnel_sock_release.
+        *
+        * So we don't need the additional reference to
+        * our own (THIS_MODULE).
+        */
+       sk_owner_put(sk);
+       /*
+        * We also call sk_owner_clear() otherwise
+        * sk_owner_put(sk) in sk_prot_free will
+        * fail, which is called via
+        * sk_free -> __sk_free -> sk_destruct
+        * and sk_destruct calls __sk_destruct
+        * directly or via call_rcu()
+        * so sk_prot_free() might be called
+        * after rxe_net_exit().
+        */
+       sk_owner_clear(sk);
 #endif /* CONFIG_DEBUG_LOCK_ALLOC */
 }