Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/connector/Kconfig b/drivers/connector/Kconfig
index 3de5f3a..ba1f3f4 100644
--- a/drivers/connector/Kconfig
+++ b/drivers/connector/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 
 menuconfig CONNECTOR
 	tristate "Connector - unified userspace <-> kernelspace linker"
diff --git a/drivers/connector/Makefile b/drivers/connector/Makefile
index 1f255e4..1bf67d3 100644
--- a/drivers/connector/Makefile
+++ b/drivers/connector/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_CONNECTOR)		+= cn.o
 obj-$(CONFIG_PROC_EVENTS)	+= cn_proc.o
 
diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index ed5e424..d58ce66 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * cn_proc.c - process events connector
  *
@@ -5,21 +6,6 @@
  * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
  * Original copyright notice follows:
  * Copyright (C) 2005 BULL SA.
- *
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
 #include <linux/kernel.h>
@@ -250,6 +236,7 @@
 {
 	struct cn_msg *msg;
 	struct proc_event *ev;
+	struct task_struct *parent;
 	__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
 
 	if (atomic_read(&proc_event_num_listeners) < 1)
@@ -262,8 +249,14 @@
 	ev->what = PROC_EVENT_COREDUMP;
 	ev->event_data.coredump.process_pid = task->pid;
 	ev->event_data.coredump.process_tgid = task->tgid;
-	ev->event_data.coredump.parent_pid = task->real_parent->pid;
-	ev->event_data.coredump.parent_tgid = task->real_parent->tgid;
+
+	rcu_read_lock();
+	if (pid_alive(task)) {
+		parent = rcu_dereference(task->real_parent);
+		ev->event_data.coredump.parent_pid = parent->pid;
+		ev->event_data.coredump.parent_tgid = parent->tgid;
+	}
+	rcu_read_unlock();
 
 	memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 	msg->ack = 0; /* not used */
@@ -276,6 +269,7 @@
 {
 	struct cn_msg *msg;
 	struct proc_event *ev;
+	struct task_struct *parent;
 	__u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
 
 	if (atomic_read(&proc_event_num_listeners) < 1)
@@ -290,8 +284,14 @@
 	ev->event_data.exit.process_tgid = task->tgid;
 	ev->event_data.exit.exit_code = task->exit_code;
 	ev->event_data.exit.exit_signal = task->exit_signal;
-	ev->event_data.exit.parent_pid = task->real_parent->pid;
-	ev->event_data.exit.parent_tgid = task->real_parent->tgid;
+
+	rcu_read_lock();
+	if (pid_alive(task)) {
+		parent = rcu_dereference(task->real_parent);
+		ev->event_data.exit.parent_pid = parent->pid;
+		ev->event_data.exit.parent_tgid = parent->tgid;
+	}
+	rcu_read_unlock();
 
 	memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 	msg->ack = 0; /* not used */
diff --git a/drivers/connector/cn_queue.c b/drivers/connector/cn_queue.c
index 9c54fdf..4929505 100644
--- a/drivers/connector/cn_queue.c
+++ b/drivers/connector/cn_queue.c
@@ -1,23 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	cn_queue.c
  *
  * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
  * All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
  */
 
 #include <linux/kernel.h>
diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index eeb7d31..2d22d6b 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -1,22 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	connector.c
  *
  * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
  * All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
 #include <linux/compiler.h>
@@ -261,16 +248,12 @@
 	return 0;
 }
 
-static struct cn_dev cdev = {
-	.input   = cn_rx_skb,
-};
-
 static int cn_init(void)
 {
 	struct cn_dev *dev = &cdev;
 	struct netlink_kernel_cfg cfg = {
 		.groups	= CN_NETLINK_USERS + 0xf,
-		.input	= dev->input,
+		.input	= cn_rx_skb,
 	};
 
 	dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, &cfg);