Re: [regression 6.1.76] dlm: cannot start dlm midcomms -97 after backport of e9cdebbe23f1 ("dlm: use kernel_connect() and kernel_bind()")

[Valentin Kleibel]

Hi Jordan, hi all

> Just a quick look comparing dlm_tcp_listen_bind between the latest 6.1
> and 6.6 stable branches,
> it looks like there is a mismatch here with the dlm_local_addr[0] parameter.
>
> 6.1
> ----
>
> static int dlm_tcp_listen_bind(struct socket *sock)
> {
> int addr_len;
>
> /* Bind to our port */
> make_sockaddr(dlm_local_addr[0], dlm_config.ci_tcp_port, &addr_len);
> return kernel_bind(sock, (struct sockaddr *)&dlm_local_addr[0],
>     addr_len);
> }
>
> 6.6
> ----
> static int dlm_tcp_listen_bind(struct socket *sock)
> {
> int addr_len;
>
> /* Bind to our port */
> make_sockaddr(&dlm_local_addr[0], dlm_config.ci_tcp_port, &addr_len);
> return kernel_bind(sock, (struct sockaddr *)&dlm_local_addr[0],
>     addr_len);
> }
>
> 6.6 contains commit c51c9cd8 (fs: dlm: don't put dlm_local_addrs on heap) which
> changed
>
> static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
>
> to
>
> static struct sockaddr_storage dlm_local_addr[DLM_MAX_ADDR_COUNT];
>
> It looks like kernel_bind() in 6.1 needs to be modified to match.

We tried to apply commit c51c9cd8 (fs: dlm: don't put dlm_local_addrs on 
heap) to the debian kernel 6.1.76 and came up with the attached patch. 
Besides the different offsets there is a slight change dlm_tcp_bind() 
where in 6.1.76 kernel_bind() is used instead of sock->ops->bind() in 
the original commit.

This patch solves the issue we experienced.

Thanks for your help,
Valentin--- a/fs/dlm/lowcomms.c	2024-02-08 10:42:19.328861479 +0100
+++ b/fs/dlm/lowcomms.c	2024-02-08 10:57:22.900463149 +0100
@@ -174,7 +174,7 @@
 static DEFINE_SPINLOCK(dlm_node_addrs_spin);
 
 static struct listen_connection listen_con;
-static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
+static struct sockaddr_storage dlm_local_addr[DLM_MAX_ADDR_COUNT];
 static int dlm_local_count;
 int dlm_allow_conn;
 
@@ -398,7 +398,7 @@
 	if (!sa_out)
 		return 0;
 
-	if (dlm_local_addr[0]->ss_family == AF_INET) {
+	if (dlm_local_addr[0].ss_family == AF_INET) {
 		struct sockaddr_in *in4  = (struct sockaddr_in *) &sas;
 		struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
 		ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
@@ -727,7 +727,7 @@
 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
 			  int *addr_len)
 {
-	saddr->ss_family =  dlm_local_addr[0]->ss_family;
+	saddr->ss_family =  dlm_local_addr[0].ss_family;
 	if (saddr->ss_family == AF_INET) {
 		struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
 		in4_addr->sin_port = cpu_to_be16(port);
@@ -1167,7 +1167,7 @@
 	int i, addr_len, result = 0;
 
 	for (i = 0; i < dlm_local_count; i++) {
-		memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
+		memcpy(&localaddr, &dlm_local_addr[i], sizeof(localaddr));
 		make_sockaddr(&localaddr, port, &addr_len);
 
 		if (!i)
@@ -1187,7 +1187,7 @@
 /* Get local addresses */
 static void init_local(void)
 {
-	struct sockaddr_storage sas, *addr;
+	struct sockaddr_storage sas;
 	int i;
 
 	dlm_local_count = 0;
@@ -1195,21 +1195,10 @@
 		if (dlm_our_addr(&sas, i))
 			break;
 
-		addr = kmemdup(&sas, sizeof(*addr), GFP_NOFS);
-		if (!addr)
-			break;
-		dlm_local_addr[dlm_local_count++] = addr;
+		memcpy(&dlm_local_addr[dlm_local_count++], &sas, sizeof(sas));
 	}
 }
 
-static void deinit_local(void)
-{
-	int i;
-
-	for (i = 0; i < dlm_local_count; i++)
-		kfree(dlm_local_addr[i]);
-}
-
 static struct writequeue_entry *new_writequeue_entry(struct connection *con)
 {
 	struct writequeue_entry *entry;
@@ -1575,7 +1564,7 @@
 	}
 
 	/* Create a socket to communicate with */
-	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
+	result = sock_create_kern(&init_net, dlm_local_addr[0].ss_family,
 				  SOCK_STREAM, dlm_proto_ops->proto, &sock);
 	if (result < 0)
 		goto socket_err;
@@ -1786,7 +1775,6 @@
 	foreach_conn(free_conn);
 	srcu_read_unlock(&connections_srcu, idx);
 	work_stop();
-	deinit_local();
 
 	dlm_proto_ops = NULL;
 }
@@ -1803,7 +1791,7 @@
 	if (result < 0)
 		return result;
 
-	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
+	result = sock_create_kern(&init_net, dlm_local_addr[0].ss_family,
 				  SOCK_STREAM, dlm_proto_ops->proto, &sock);
 	if (result < 0) {
 		log_print("Can't create comms socket: %d", result);
@@ -1842,7 +1830,7 @@
 	/* Bind to our cluster-known address connecting to avoid
 	 * routing problems.
 	 */
-	memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
+	memcpy(&src_addr, &dlm_local_addr[0], sizeof(src_addr));
 	make_sockaddr(&src_addr, 0, &addr_len);
 
 	result = kernel_bind(sock, (struct sockaddr *)&src_addr,
@@ -1899,7 +1887,7 @@
 	int addr_len;
 
 	/* Bind to our port */
-	make_sockaddr(dlm_local_addr[0], dlm_config.ci_tcp_port, &addr_len);
+	make_sockaddr(&dlm_local_addr[0], dlm_config.ci_tcp_port, &addr_len);
 	return kernel_bind(sock, (struct sockaddr *)&dlm_local_addr[0],
 			   addr_len);
 }
@@ -1992,7 +1980,7 @@
 
 	error = work_start();
 	if (error)
-		goto fail_local;
+		goto fail;
 
 	dlm_allow_conn = 1;
 
@@ -2022,8 +2010,6 @@
 fail_proto_ops:
 	dlm_allow_conn = 0;
 	work_stop();
-fail_local:
-	deinit_local();
 fail:
 	return error;
 }