diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 80335b4ee4fd..bea2a02850af 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -226,6 +226,9 @@ struct rxrpc_security {
 	int (*verify_packet)(struct rxrpc_call *, struct sk_buff *,
 			     unsigned int, unsigned int, rxrpc_seq_t, u16);
 
+	/* Free crypto request on a call */
+	void (*free_call_crypto)(struct rxrpc_call *);
+
 	/* Locate the data in a received packet that has been verified. */
 	void (*locate_data)(struct rxrpc_call *, struct sk_buff *,
 			    unsigned int *, unsigned int *);
@@ -557,6 +560,7 @@ struct rxrpc_call {
 	unsigned long		expect_term_by;	/* When we expect call termination by */
 	u32			next_rx_timo;	/* Timeout for next Rx packet (jif) */
 	u32			next_req_timo;	/* Timeout for next Rx request packet (jif) */
+	struct skcipher_request	*cipher_req;	/* Packet cipher request buffer */
 	struct timer_list	timer;		/* Combined event timer */
 	struct work_struct	processor;	/* Event processor */
 	rxrpc_notify_rx_t	notify_rx;	/* kernel service Rx notification function */
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index 217b12be9e08..60cbc81dc461 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -476,8 +476,10 @@ void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
 
 	_debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn);
 
-	if (conn)
+	if (conn) {
 		rxrpc_disconnect_call(call);
+		conn->security->free_call_crypto(call);
+	}
 
 	for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++) {
 		rxrpc_free_skb(call->rxtx_buffer[i],
diff --git a/net/rxrpc/insecure.c b/net/rxrpc/insecure.c
index a29d26c273b5..f6c59f5fae9d 100644
--- a/net/rxrpc/insecure.c
+++ b/net/rxrpc/insecure.c
@@ -33,6 +33,10 @@ static int none_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
 	return 0;
 }
 
+static void none_free_call_crypto(struct rxrpc_call *call)
+{
+}
+
 static void none_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
 			     unsigned int *_offset, unsigned int *_len)
 {
@@ -83,6 +87,7 @@ const struct rxrpc_security rxrpc_no_security = {
 	.exit				= none_exit,
 	.init_connection_security	= none_init_connection_security,
 	.prime_packet_security		= none_prime_packet_security,
+	.free_call_crypto		= none_free_call_crypto,
 	.secure_packet			= none_secure_packet,
 	.verify_packet			= none_verify_packet,
 	.locate_data			= none_locate_data,
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index ae8cd8926456..dbb109da1835 100644
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -43,6 +43,7 @@ struct rxkad_level2_hdr {
  * packets
  */
 static struct crypto_sync_skcipher *rxkad_ci;
+static struct skcipher_request *rxkad_ci_req;
 static DEFINE_MUTEX(rxkad_ci_mutex);
 
 /*
@@ -99,8 +100,8 @@ static int rxkad_init_connection_security(struct rxrpc_connection *conn)
  */
 static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
 {
+	struct skcipher_request *req;
 	struct rxrpc_key_token *token;
-	SYNC_SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
 	struct scatterlist sg;
 	struct rxrpc_crypt iv;
 	__be32 *tmpbuf;
@@ -115,6 +116,12 @@ static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
 	if (!tmpbuf)
 		return -ENOMEM;
 
+	req = skcipher_request_alloc(&conn->cipher->base, GFP_NOFS);
+	if (!req) {
+		kfree(tmpbuf);
+		return -ENOMEM;
+	}
+
 	token = conn->params.key->payload.data[0];
 	memcpy(&iv, token->kad->session_key, sizeof(iv));
 
@@ -128,7 +135,7 @@ static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
 	skcipher_request_set_callback(req, 0, NULL, NULL);
 	skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
 	crypto_skcipher_encrypt(req);
-	skcipher_request_zero(req);
+	skcipher_request_free(req);
 
 	memcpy(&conn->csum_iv, tmpbuf + 2, sizeof(conn->csum_iv));
 	kfree(tmpbuf);
@@ -136,6 +143,35 @@ static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
 	return 0;
 }
 
+/*
+ * Allocate and prepare the crypto request on a call.  For any particular call,
+ * this is called serially for the packets, so no lock should be necessary.
+ */
+static struct skcipher_request *rxkad_get_call_crypto(struct rxrpc_call *call)
+{
+	struct crypto_skcipher *tfm = &call->conn->cipher->base;
+	struct skcipher_request	*cipher_req = call->cipher_req;
+
+	if (!cipher_req) {
+		cipher_req = skcipher_request_alloc(tfm, GFP_NOFS);
+		if (!cipher_req)
+			return NULL;
+		call->cipher_req = cipher_req;
+	}
+
+	return cipher_req;
+}
+
+/*
+ * Clean up the crypto on a call.
+ */
+static void rxkad_free_call_crypto(struct rxrpc_call *call)
+{
+	if (call->cipher_req)
+		skcipher_request_free(call->cipher_req);
+	call->cipher_req = NULL;
+}
+
 /*
  * partially encrypt a packet (level 1 security)
  */
@@ -246,7 +282,7 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
 			       void *sechdr)
 {
 	struct rxrpc_skb_priv *sp;
-	SYNC_SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
+	struct skcipher_request	*req;
 	struct rxrpc_crypt iv;
 	struct scatterlist sg;
 	u32 x, y;
@@ -265,6 +301,10 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
 	if (ret < 0)
 		return ret;
 
+	req = rxkad_get_call_crypto(call);
+	if (!req)
+		return -ENOMEM;
+
 	/* continue encrypting from where we left off */
 	memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
 
@@ -502,7 +542,7 @@ static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
 			       unsigned int offset, unsigned int len,
 			       rxrpc_seq_t seq, u16 expected_cksum)
 {
-	SYNC_SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
+	struct skcipher_request	*req;
 	struct rxrpc_crypt iv;
 	struct scatterlist sg;
 	bool aborted;
@@ -515,6 +555,10 @@ static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
 	if (!call->conn->cipher)
 		return 0;
 
+	req = rxkad_get_call_crypto(call);
+	if (!req)
+		return -ENOMEM;
+
 	/* continue encrypting from where we left off */
 	memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
 
@@ -747,14 +791,18 @@ static void rxkad_calc_response_checksum(struct rxkad_response *response)
 /*
  * encrypt the response packet
  */
-static void rxkad_encrypt_response(struct rxrpc_connection *conn,
-				   struct rxkad_response *resp,
-				   const struct rxkad_key *s2)
+static int rxkad_encrypt_response(struct rxrpc_connection *conn,
+				  struct rxkad_response *resp,
+				  const struct rxkad_key *s2)
 {
-	SYNC_SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
+	struct skcipher_request *req;
 	struct rxrpc_crypt iv;
 	struct scatterlist sg[1];
 
+	req = skcipher_request_alloc(&conn->cipher->base, GFP_NOFS);
+	if (!req)
+		return -ENOMEM;
+
 	/* continue encrypting from where we left off */
 	memcpy(&iv, s2->session_key, sizeof(iv));
 
@@ -764,7 +812,8 @@ static void rxkad_encrypt_response(struct rxrpc_connection *conn,
 	skcipher_request_set_callback(req, 0, NULL, NULL);
 	skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
 	crypto_skcipher_encrypt(req);
-	skcipher_request_zero(req);
+	skcipher_request_free(req);
+	return 0;
 }
 
 /*
@@ -839,8 +888,9 @@ static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
 
 	/* calculate the response checksum and then do the encryption */
 	rxkad_calc_response_checksum(resp);
-	rxkad_encrypt_response(conn, resp, token->kad);
-	ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
+	ret = rxkad_encrypt_response(conn, resp, token->kad);
+	if (ret == 0)
+		ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
 	kfree(resp);
 	return ret;
 
@@ -1017,18 +1067,16 @@ static void rxkad_decrypt_response(struct rxrpc_connection *conn,
 				   struct rxkad_response *resp,
 				   const struct rxrpc_crypt *session_key)
 {
-	SYNC_SKCIPHER_REQUEST_ON_STACK(req, rxkad_ci);
+	struct skcipher_request *req = rxkad_ci_req;
 	struct scatterlist sg[1];
 	struct rxrpc_crypt iv;
 
 	_enter(",,%08x%08x",
 	       ntohl(session_key->n[0]), ntohl(session_key->n[1]));
 
-	ASSERT(rxkad_ci != NULL);
-
 	mutex_lock(&rxkad_ci_mutex);
 	if (crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
-				   sizeof(*session_key)) < 0)
+					sizeof(*session_key)) < 0)
 		BUG();
 
 	memcpy(&iv, session_key, sizeof(iv));
@@ -1222,10 +1270,26 @@ static void rxkad_clear(struct rxrpc_connection *conn)
  */
 static int rxkad_init(void)
 {
+	struct crypto_sync_skcipher *tfm;
+	struct skcipher_request *req;
+
 	/* pin the cipher we need so that the crypto layer doesn't invoke
 	 * keventd to go get it */
-	rxkad_ci = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
-	return PTR_ERR_OR_ZERO(rxkad_ci);
+	tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
+	if (IS_ERR(tfm))
+		return PTR_ERR(tfm);
+
+	req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
+	if (!req)
+		goto nomem_tfm;
+
+	rxkad_ci_req = req;
+	rxkad_ci = tfm;
+	return 0;
+
+nomem_tfm:
+	crypto_free_sync_skcipher(tfm);
+	return -ENOMEM;
 }
 
 /*
@@ -1233,8 +1297,8 @@ static int rxkad_init(void)
  */
 static void rxkad_exit(void)
 {
-	if (rxkad_ci)
-		crypto_free_sync_skcipher(rxkad_ci);
+	crypto_free_sync_skcipher(rxkad_ci);
+	skcipher_request_free(rxkad_ci_req);
 }
 
 /*
@@ -1249,6 +1313,7 @@ const struct rxrpc_security rxkad = {
 	.prime_packet_security		= rxkad_prime_packet_security,
 	.secure_packet			= rxkad_secure_packet,
 	.verify_packet			= rxkad_verify_packet,
+	.free_call_crypto		= rxkad_free_call_crypto,
 	.locate_data			= rxkad_locate_data,
 	.issue_challenge		= rxkad_issue_challenge,
 	.respond_to_challenge		= rxkad_respond_to_challenge,