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Commit eeee2452 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

SUNRPC: Fix a deadlock in rpc_client_register() 



Commit 38481605 (SUNRPC: fix races on
PipeFS MOUNT notifications) introduces a regression when we call
rpc_setup_pipedir() with RPCSEC_GSS as the auth flavour.

By calling rpcauth_create() while holding the sn->pipefs_sb_lock, we
end up deadlocking in gss_pipes_dentries_create_net().
Fix is to register the client and release the mutex before calling
rpcauth_create().

Reported-by: default avatarWeston Andros Adamson <dros@netapp.com>
Tested-by: default avatarWeston Andros Adamson <dros@netapp.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: <stable@vger.kernel.org> # : 38481605: SUNRPC: fix races on PipeFS MOUNT
Cc: <stable@vger.kernel.org> # : e73f4cc0: SUNRPC: split client creation
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 4f8568cb

net/sunrpc/clnt.c

+9 −7
Original line number Diff line number Diff line
@@ -290,7 +290,7 @@ static int rpc_client_register(const struct rpc_create_args *args, 
	struct rpc_auth *auth;

	struct net *net = rpc_net_ns(clnt);

	struct super_block *pipefs_sb;

	int err = 0;

	int err;



	pipefs_sb = rpc_get_sb_net(net);

	if (pipefs_sb) {
@@ -299,6 +299,10 @@ static int rpc_client_register(const struct rpc_create_args *args, 
			goto out;

	}



	rpc_register_client(clnt);

	if (pipefs_sb)

		rpc_put_sb_net(net);



	auth = rpcauth_create(args->authflavor, clnt);

	if (IS_ERR(auth)) {

		dprintk("RPC:       Couldn't create auth handle (flavor %u)\n",
@@ -306,16 +310,14 @@ static int rpc_client_register(const struct rpc_create_args *args, 
		err = PTR_ERR(auth);

		goto err_auth;

	}



	rpc_register_client(clnt);

	return 0;

err_auth:

	pipefs_sb = rpc_get_sb_net(net);

	__rpc_clnt_remove_pipedir(clnt);

out:

	if (pipefs_sb)

		rpc_put_sb_net(net);

	return err;



err_auth:

	__rpc_clnt_remove_pipedir(clnt);

	goto out;

}



static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)