Re: [PATCH] RDMA/rxe: let rxe_reclassify_recv_socket() call sk_owner_put()

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2025/12/19 6:04, Stefan Metzmacher 写道:
> 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>

Thanks a lot. IIRC, there is a similar commit for SIW driver. Thus, I am 
not sure if there is a similar problem in SIW driver or not.

Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>

Zhu Yanjun

> ---
>   drivers/infiniband/sw/rxe/rxe_net.c | 32 +++++++++++++++++++++++++++++
>   1 file changed, 32 insertions(+)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
> index 0195d361e5e3..0bd0902b11f7 100644
> --- 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 */
>   }
>