LU-18383 ksocklnd: Avoid TCP socket orphans in racy LNet

LU-18137 3367ef3eb2 introduced code to handle upstream kernel changes
with regards to releasing kernel sockets.  Under heavy/racy LNet
hello transactions between servers and clients, client TCP sockets
can transition to a orphan state that is never reaped.  This commit
moves LU-18137's fix closer to the kernel socket allocation to
avoid this racy connection setup condition.

This commit also provides a backport of the kernel's socket
accounting function sock_inuse_add() for compatibility when vendor
kernels lack the static function definition in their kernel headers.
The lnet_compat.h file has been introduced for a place to put such
compatibility code.

Fixes: 3367ef3eb2 ("LU-18137 ksocklnd: Fix TCP socket cleanup")
Signed-off-by: Josh Samuelson <josh@1up.unl.edu>
Change-Id: I11fc0b53e051871da26c079e9aeb50976b20bbd3
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56737
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Mark Roper <ropermar@amazon.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lnet/autoconf/lustre-lnet.m4 b/lnet/autoconf/lustre-lnet.m4
index cb4e936..161dee7 100644 (file)
--- a/lnet/autoconf/lustre-lnet.m4
+++ b/lnet/autoconf/lustre-lnet.m4
@@ -1027,6 +1027,27 @@ AC_DEFUN([LN_CONFIG_SOCK_CREATE_KERN], [
 ]) # LN_CONFIG_SOCK_CREATE_KERN
 
 #
+# LN_CONFIG_SOCK_INUSE_ADD
+#
+# Linux v5.17-rc1-gd477eb900484 added helper function sock_inuse_add()
+# for socket statistics.
+#
+AC_DEFUN([LN_SRC_CONFIG_SOCK_INUSE_ADD], [
+       LB2_LINUX_TEST_SRC([sock_inuse_add], [
+               #include <net/sock.h>
+       ],[
+               sock_inuse_add((struct net*)0, 0);
+       ],[-Werror])
+])
+AC_DEFUN([LN_CONFIG_SOCK_INUSE_ADD], [
+       LB2_MSG_LINUX_TEST_RESULT([if 'sock_inuse_add()' is available],
+       [sock_inuse_add], [
+               AC_DEFINE(HAVE_SOCK_INUSE_ADD, 1,
+                       [sock_inuse_add() is available])
+       ])
+]) # LN_CONFIG_SOCK_INUSE_ADD
+
+#
 # LN_CONFIG_SOCK_NOT_OWNED_BY_ME
 #
 # Linux upstream v6.11-rc3-g151c9c724d05d5b0d changes TCP socket orphan
@@ -1227,6 +1248,7 @@ AC_DEFUN([LN_PROG_LINUX_SRC], [
        LN_SRC_CONFIG_SK_DATA_READY
        # 4.x
        LN_SRC_CONFIG_SOCK_CREATE_KERN
+       LN_SRC_CONFIG_SOCK_INUSE_ADD
        LN_SRC_CONFIG_SOCK_NOT_OWNED_BY_ME
        # 4.6
        LN_SRC_ETHTOOL_LINK_SETTINGS
@@ -1247,6 +1269,7 @@ AC_DEFUN([LN_PROG_LINUX_RESULTS], [
        LN_CONFIG_SK_DATA_READY
        # 4.x
        LN_CONFIG_SOCK_CREATE_KERN
+       LN_CONFIG_SOCK_INUSE_ADD
        LN_CONFIG_SOCK_NOT_OWNED_BY_ME
        # 4.6
        LN_ETHTOOL_LINK_SETTINGS

diff --git a/lnet/include/lnet/Makefile.am b/lnet/include/lnet/Makefile.am
index 6baeae1..b9508da 100644 (file)
--- a/lnet/include/lnet/Makefile.am
+++ b/lnet/include/lnet/Makefile.am
@@ -10,6 +10,7 @@ EXTRA_DIST = \
        lib-lnet.h \
        lib-types.h \
        udsp.h \
+       lnet_compat.h \
        lnet_crypto.h \
        lnet_rdma.h \
        lnet_gds.h \

diff --git a/lnet/include/lnet/lnet_compat.h b/lnet/include/lnet/lnet_compat.h
new file mode 100644 (file)
index 0000000..d0d25c7
--- /dev/null
+++ b/lnet/include/lnet/lnet_compat.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* This file is part of Lustre, http://www.lustre.org/ */
+
+#ifndef __LNET_LNET_COMPAT_H__
+#define __LNET_LNET_COMPAT_H__
+
+/* kernel v5.17-rc1: commit d477eb9004845cb2dc92ad5eed79a437738a868a
+ * added static function sock_inuse_add() to the kernel headers, backport
+ * a copy for vendor kernels that may not provide it; such kernels will
+ * be lacking the all member added to the prot_inuse structure in the
+ * next commit, 4199bae10c49e24bc2c5d8c06a68820d56640000.
+ */
+#ifdef HAVE_SOCK_NOT_OWNED_BY_ME
+#ifndef HAVE_SOCK_INUSE_ADD
+#ifdef CONFIG_PROC_FS
+static inline void sock_inuse_add(const struct net *net, int val)
+{
+       this_cpu_add(*net->core.sock_inuse, val);
+}
+#else
+static inline void sock_inuse_add(const struct net *net, int val)
+{
+}
+#endif
+#endif
+#endif
+
+#endif

diff --git a/lnet/klnds/socklnd/socklnd.h b/lnet/klnds/socklnd/socklnd.h
index 6a68e40..5fd6b39 100644 (file)
--- a/lnet/klnds/socklnd/socklnd.h
+++ b/lnet/klnds/socklnd/socklnd.h
@@ -38,7 +38,6 @@
 #include <linux/uio.h>
 #include <linux/unistd.h>
 #include <linux/hashtable.h>
-#include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/tcp.h>
 

diff --git a/lnet/klnds/socklnd/socklnd_lib.c b/lnet/klnds/socklnd/socklnd_lib.c
index 4954905..d2ff979 100644 (file)
--- a/lnet/klnds/socklnd/socklnd_lib.c
+++ b/lnet/klnds/socklnd/socklnd_lib.c
@@ -429,18 +429,10 @@ ksocknal_lib_setup_sock(struct socket *sock, struct lnet_ni *ni)
        int keep_intvl;
        int keep_count;
        int do_keepalive;
-       struct sock     *sk = sock->sk;
-       struct tcp_sock *tp = tcp_sk(sk);
+       struct tcp_sock *tp = tcp_sk(sock->sk);
        struct lnet_ioctl_config_socklnd_tunables *lndtun;
-#ifdef HAVE_SOCK_NOT_OWNED_BY_ME
-       struct net      *net = sock_net(sk);
-
-       /* Set sk_net_refcnt and namespace for orphan cleanup LU-18137 */
-       sk->sk_net_refcnt = 1;
-       get_net(net);
-#endif
 
-       sk->sk_allocation = GFP_NOFS;
+       sock->sk->sk_allocation = GFP_NOFS;
 
        /* Ensure this socket aborts active sends immediately when closed. */
        sock_reset_flag(sock->sk, SOCK_LINGER);

diff --git a/lnet/lnet/lib-socket.c b/lnet/lnet/lib-socket.c
index d44d8dd..d9fa38b 100644 (file)
--- a/lnet/lnet/lib-socket.c
+++ b/lnet/lnet/lib-socket.c
@@ -19,6 +19,7 @@
 #include <linux/pagemap.h>
 /* For sys_open & sys_close */
 #include <linux/syscalls.h>
+#include <net/net_namespace.h>
 #include <net/sock.h>
 #include <linux/inetdevice.h>
 
@@ -26,6 +27,7 @@
 #include <libcfs/linux/linux-net.h>
 #include <libcfs/libcfs.h>
 #include <lnet/lib-lnet.h>
+#include <lnet/lnet_compat.h>
 
 int
 lnet_sock_write(struct socket *sock, void *buffer, int nob, int timeout)
@@ -190,6 +192,12 @@ retry:
        }
 
        sock->sk->sk_reuseport = 1;
+#ifdef HAVE_SOCK_NOT_OWNED_BY_ME
+       /* Set sk_net_refcnt and namespace for orphan cleanup LU-18137 */
+       sock->sk->sk_net_refcnt = 1;
+       get_net(ns);
+       sock_inuse_add(ns, 1);
+#endif
 
        if (interface >= 0 || local_port != 0) {
                struct sockaddr_storage locaddr = {};