80 files changed, 143 insertions, 140 deletions

diff --git a/kernel/Kconfig.freezer b/kernel/Kconfig.freezer
index a3bb4cb52539..68646feefb3d 100644
--- a/kernel/Kconfig.freezer
+++ b/kernel/Kconfig.freezer
@@ -1,2 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config FREEZER
         def_bool PM_SLEEP || CGROUP_FREEZER
diff --git a/kernel/Kconfig.hz b/kernel/Kconfig.hz
index 2a202a846757..38ef6d06888e 100644
--- a/kernel/Kconfig.hz
+++ b/kernel/Kconfig.hz
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Timer Interrupt Frequency Configuration
 #
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index bf770d7556f7..e0852dc333ac 100644
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # The ARCH_INLINE foo is necessary because select ignores "depends on"
 #
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index 0fee5fe6c899..dc0b682ec2d9 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 
 choice
         prompt "Preemption Model"
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 191b79948424..1e525d70f833 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -164,6 +164,9 @@ static void dev_map_free(struct bpf_map *map)
         bpf_clear_redirect_map(map);
         synchronize_rcu();
 
+        /* Make sure prior __dev_map_entry_free() have completed. */
+        rcu_barrier();
+
         /* To ensure all pending flush operations have completed wait for flush
          * bitmap to indicate all flush_needed bits to be zero on _all_ cpus.
          * Because the above synchronize_rcu() ensures the map is disconnected
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 192d32e77db3..0f2708fde5f7 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -527,18 +527,30 @@ static u32 htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
         return insn - insn_buf;
 }
 
-static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
+static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
+                                                        void *key, const bool mark)
 {
         struct htab_elem *l = __htab_map_lookup_elem(map, key);
 
         if (l) {
-                bpf_lru_node_set_ref(&l->lru_node);
+                if (mark)
+                        bpf_lru_node_set_ref(&l->lru_node);
                 return l->key + round_up(map->key_size, 8);
         }
 
         return NULL;
 }
 
+static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
+{
+        return __htab_lru_map_lookup_elem(map, key, true);
+}
+
+static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
+{
+        return __htab_lru_map_lookup_elem(map, key, false);
+}
+
 static u32 htab_lru_map_gen_lookup(struct bpf_map *map,
                                    struct bpf_insn *insn_buf)
 {
@@ -1250,6 +1262,7 @@ const struct bpf_map_ops htab_lru_map_ops = {
         .map_free = htab_map_free,
         .map_get_next_key = htab_map_get_next_key,
         .map_lookup_elem = htab_lru_map_lookup_elem,
+        .map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
         .map_update_elem = htab_lru_map_update_elem,
         .map_delete_elem = htab_lru_map_delete_elem,
         .map_gen_lookup = htab_lru_map_gen_lookup,
@@ -1281,7 +1294,6 @@ static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
 
 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
 {
-        struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
         struct htab_elem *l;
         void __percpu *pptr;
         int ret = -ENOENT;
@@ -1297,8 +1309,9 @@ int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
         l = __htab_map_lookup_elem(map, key);
         if (!l)
                 goto out;
-        if (htab_is_lru(htab))
-                bpf_lru_node_set_ref(&l->lru_node);
+        /* We do not mark LRU map element here in order to not mess up
+         * eviction heuristics when user space does a map walk.
+         */
         pptr = htab_elem_get_ptr(l, map->key_size);
         for_each_possible_cpu(cpu) {
                 bpf_long_memcpy(value + off,
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index bc53e5b20ddc..84a80b02db99 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -518,7 +518,7 @@ out:
 static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type type)
 {
         struct bpf_prog *prog;
-        int ret = inode_permission(inode, MAY_READ | MAY_WRITE);
+        int ret = inode_permission(inode, MAY_READ);
         if (ret)
                 return ERR_PTR(ret);
 
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ad3ccf82f31d..cb5440b02e82 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -808,7 +808,10 @@ static int map_lookup_elem(union bpf_attr *attr)
                 err = map->ops->map_peek_elem(map, value);
         } else {
                 rcu_read_lock();
-                ptr = map->ops->map_lookup_elem(map, key);
+                if (map->ops->map_lookup_elem_sys_only)
+                        ptr = map->ops->map_lookup_elem_sys_only(map, key);
+                else
+                        ptr = map->ops->map_lookup_elem(map, key);
                 if (IS_ERR(ptr)) {
                         err = PTR_ERR(ptr);
                 } else if (!ptr) {
diff --git a/kernel/bpf/tnum.c b/kernel/bpf/tnum.c
index 938d41211be7..ca52b9642943 100644
--- a/kernel/bpf/tnum.c
+++ b/kernel/bpf/tnum.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* tnum: tracked (or tristate) numbers
  *
  * A tnum tracks knowledge about the bits of a value.  Each bit can be either
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 68ca5de7ec27..88006be40ea3 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include "cgroup-internal.h"
 
 #include <linux/ctype.h>
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index bb95a35e8c2d..ca19b4c8acf5 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include "cgroup-internal.h"
 
 #include <linux/sched/cputime.h>
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 9ad37b9e44a7..be01a4d627c9 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Context tracking: Probe on high level context boundaries such as kernel
  * and userspace. This includes syscalls and exceptions entry/exit.
diff --git a/kernel/crash_dump.c b/kernel/crash_dump.c
index b64e238b553b..9c23ae074b40 100644
--- a/kernel/crash_dump.c
+++ b/kernel/crash_dump.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/kernel.h>
 #include <linux/crash_dump.h>
 #include <linux/init.h>
diff --git a/kernel/cred.c b/kernel/cred.c
index 45d77284aed0..e74ffdc98a92 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -1,12 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* Task credentials management - see Documentation/security/credentials.rst
  *
  * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
  */
 #include <linux/export.h>
 #include <linux/cred.h>
diff --git a/kernel/debug/Makefile b/kernel/debug/Makefile
index a85edc339985..332ee6c6ec2c 100644
--- a/kernel/debug/Makefile
+++ b/kernel/debug/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Makefile for the linux kernel debugger
 #
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index 2a12b988c717..27725754ac99 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -1,16 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* delayacct.c - per-task delay accounting
  *
  * Copyright (C) Shailabh Nagar, IBM Corp. 2006
- *
- * 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 would 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.
  */
 
 #include <linux/sched.h>
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 83d711f8d665..70f8f8d9200e 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 
 config HAS_DMA
         bool
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 6f7619c1f877..13f0cb080a4d 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Dynamic DMA mapping support.
  *
diff --git a/kernel/exit.c b/kernel/exit.c
index 8361a560cd1d..1803efb2922f 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/kernel/exit.c
  *
diff --git a/kernel/fork.c b/kernel/fork.c
index b4cba953040a..b2b87d450b80 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/kernel/fork.c
  *
diff --git a/kernel/freezer.c b/kernel/freezer.c
index b162b74611e4..c0738424bb43 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * kernel/freezer.c - Function to freeze a process
  *
diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
index f71c1adcff31..3941a9c48f83 100644
--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 menu "GCOV-based kernel profiling"
 
 config GCOV_KERNEL
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index f108a95882c6..14a625c16cb3 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Detect Hung Task
  *
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 8fee06625c37..f92d9a687372 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 menu "IRQ subsystem"
 # Options selectable by the architecture code
 
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 73288914ed5e..d42acaf81886 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2010 Red Hat, Inc., Peter Zijlstra
  *
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index de6efdecc70d..0bfa10f4410c 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * jump label support
  *
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 14934afa9e68..95a260f9214b 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
  *
diff --git a/kernel/kthread.c b/kernel/kthread.c
index be4e8795561a..621467c33fef 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Kernel thread helper functions.
  *   Copyright (C) 2004 IBM Corporation, Rusty Russell.
  *
diff --git a/kernel/livepatch/Kconfig b/kernel/livepatch/Kconfig
index ec4565122e65..54102deb50ba 100644
--- a/kernel/livepatch/Kconfig
+++ b/kernel/livepatch/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config HAVE_LIVEPATCH
         bool
         help
diff --git a/kernel/livepatch/Makefile b/kernel/livepatch/Makefile
index b36ceda6488e..cf9b5bcdb952 100644
--- a/kernel/livepatch/Makefile
+++ b/kernel/livepatch/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_LIVEPATCH) += livepatch.o
 
 livepatch-objs := core.o patch.o shadow.o transition.o
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 91cd519756d3..2398832947c6 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -1,21 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * core.c - Kernel Live Patching Core
  *
  * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
  * Copyright (C) 2014 SUSE
- *
- * 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, see <http://www.gnu.org/licenses/>.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
index 99cb3ad05eb4..bd43537702bd 100644
--- a/kernel/livepatch/patch.c
+++ b/kernel/livepatch/patch.c
@@ -1,22 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * patch.c - livepatch patching functions
  *
  * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
  * Copyright (C) 2014 SUSE
  * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
- *
- * 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, see <http://www.gnu.org/licenses/>.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
diff --git a/kernel/livepatch/shadow.c b/kernel/livepatch/shadow.c
index 83958c814439..e5c9fb295ba9 100644
--- a/kernel/livepatch/shadow.c
+++ b/kernel/livepatch/shadow.c
@@ -1,22 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * shadow.c - Shadow Variables
  *
  * Copyright (C) 2014 Josh Poimboeuf <jpoimboe@redhat.com>
  * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
  * Copyright (C) 2017 Joe Lawrence <joe.lawrence@redhat.com>
- *
- * 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, see <http://www.gnu.org/licenses/>.
  */
 
 /**
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index c53370d596be..abb2a4a2cbb2 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -1,20 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * transition.c - Kernel Live Patching transition functions
  *
  * Copyright (C) 2015-2016 Josh Poimboeuf <jpoimboe@redhat.com>
- *
- * 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, see <http://www.gnu.org/licenses/>.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
diff --git a/kernel/locking/lock_events.h b/kernel/locking/lock_events.h
index feb1acc54611..46b71af8eef2 100644
--- a/kernel/locking/lock_events.h
+++ b/kernel/locking/lock_events.h
@@ -31,12 +31,50 @@ enum lock_events {
 DECLARE_PER_CPU(unsigned long, lockevents[lockevent_num]);
 
 /*
+ * The purpose of the lock event counting subsystem is to provide a low
+ * overhead way to record the number of specific locking events by using
+ * percpu counters. It is the percpu sum that matters, not specifically
+ * how many of them happens in each cpu.
+ *
+ * It is possible that the same percpu counter may be modified in both
+ * the process and interrupt contexts. For architectures that perform
+ * percpu operation with multiple instructions, it is possible to lose
+ * count if a process context percpu update is interrupted in the middle
+ * and the same counter is updated in the interrupt context. Therefore,
+ * the generated percpu sum may not be precise. The error, if any, should
+ * be small and insignificant.
+ *
+ * For those architectures that do multi-instruction percpu operation,
+ * preemption in the middle and moving the task to another cpu may cause
+ * a larger error in the count. Again, this will be few and far between.
+ * Given the imprecise nature of the count and the possibility of resetting
+ * the count and doing the measurement again, this is not really a big
+ * problem.
+ *
+ * To get a better picture of what is happening under the hood, it is
+ * suggested that a few measurements should be taken with the counts
+ * reset in between to stamp out outliner because of these possible
+ * error conditions.
+ *
+ * To minimize overhead, we use __this_cpu_*() in all cases except when
+ * CONFIG_DEBUG_PREEMPT is defined. In this particular case, this_cpu_*()
+ * will be used to avoid the appearance of unwanted BUG messages.
+ */
+#ifdef CONFIG_DEBUG_PREEMPT
+#define lockevent_percpu_inc(x)         this_cpu_inc(x)
+#define lockevent_percpu_add(x, v)      this_cpu_add(x, v)
+#else
+#define lockevent_percpu_inc(x)         __this_cpu_inc(x)
+#define lockevent_percpu_add(x, v)      __this_cpu_add(x, v)
+#endif
+
+/*
  * Increment the PV qspinlock statistical counters
  */
 static inline void __lockevent_inc(enum lock_events event, bool cond)
 {
         if (cond)
-                __this_cpu_inc(lockevents[event]);
+                lockevent_percpu_inc(lockevents[event]);
 }
 
 #define lockevent_inc(ev)         __lockevent_inc(LOCKEVENT_ ##ev, true)
@@ -44,7 +82,7 @@ static inline void __lockevent_inc(enum lock_events event, bool cond)
 
 static inline void __lockevent_add(enum lock_events event, int inc)
 {
-        __this_cpu_add(lockevents[event], inc);
+        lockevent_percpu_add(lockevents[event], inc);
 }
 
 #define lockevent_add(ev, c)    __lockevent_add(LOCKEVENT_ ##ev, c)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index d06190fa5082..c47788fa85f9 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * kernel/lockdep.c
  *
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index db578783dd36..0c601ae072b3 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * kernel/locking/mutex.c
  *
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index f17dad99eec8..b6a9cc62099a 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/atomic.h>
 #include <linux/rwsem.h>
 #include <linux/percpu.h>
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 978d63a8261c..38fbf9fa7f1b 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * RT-Mutexes: simple blocking mutual exclusion locks with PI support
  *
diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
index 65a3b7e55b9f..3e82f449b4ff 100644
--- a/kernel/locking/test-ww_mutex.c
+++ b/kernel/locking/test-ww_mutex.c
@@ -1,19 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Module-based API test facility for ww_mutexes
- *
- * 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, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
  */
 
 #include <linux/kernel.h>
diff --git a/kernel/module-internal.h b/kernel/module-internal.h
index d354341f8cc0..33783abc377b 100644
--- a/kernel/module-internal.h
+++ b/kernel/module-internal.h
@@ -1,12 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /* Module internals
  *
  * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
  */
 
 #include <linux/elf.h>
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index 6b9a926fd86b..b10fb1986ca9 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -1,12 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* Module signature checker
  *
  * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
  */
 
 #include <linux/kernel.h>
diff --git a/kernel/notifier.c b/kernel/notifier.c
index bfc95b3e4235..d9f5081d578d 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/kdebug.h>
 #include <linux/kprobes.h>
 #include <linux/export.h>
diff --git a/kernel/panic.c b/kernel/panic.c
index b4543a31a495..4d9f55bf7d38 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/kernel/panic.c
  *
diff --git a/kernel/pid.c b/kernel/pid.c
index 89548d35eefb..e5cad0c7d5dd 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Generic pidhash and scalable, time-bounded PID allocator
  *
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index aa6e72fb7c08..f54bc7cb6c2d 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Pid namespaces
  *
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 9bbaaab14b36..ff8592ddedee 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config SUSPEND
         bool "Suspend to RAM and standby"
         depends on ARCH_SUSPEND_POSSIBLE
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index 9d22131afc1e..33e3febaba53 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * This module exposes the interface to kernel space for specifying
  * QoS dependencies.  It provides infrastructure for registration of:
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index 4a2ffc39eb95..4d052fc6bcde 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 obj-y   = printk.o
 obj-$(CONFIG_PRINTK)    += printk_safe.o
 obj-$(CONFIG_A11Y_BRAILLE_CONSOLE)      += braille.o
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 0f1898820cba..c8e6ab689d42 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -1,18 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  * internal.h - printk internal definitions
- *
- * 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, see <http://www.gnu.org/licenses/>.
  */
 #include <linux/percpu.h>
 
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index a6e06fe38e41..1888f6a3b694 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/kernel/printk.c
  *
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index 0913b4d385de..b4045e782743 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -1,18 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * printk_safe.c - Safe printk for printk-deadlock-prone contexts
- *
- * 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, see <http://www.gnu.org/licenses/>.
  */
 
 #include <linux/preempt.h>
diff --git a/kernel/profile.c b/kernel/profile.c
index 9c08a2c7cb1d..af7c94bf5fa1 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/kernel/profile.c
  *  Simple profiling. Manages a direct-mapped profile hit count buffer,
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 6f357f4fc859..5710d07e67cf 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * linux/kernel/ptrace.c
  *
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index 37301430970e..480edf328b51 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # RCU-related configuration options
 #
diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
index 0ec7d1d33a14..5ec3ea4028e2 100644
--- a/kernel/rcu/Kconfig.debug
+++ b/kernel/rcu/Kconfig.debug
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # RCU-related debugging configuration options
 #
diff --git a/kernel/reboot.c b/kernel/reboot.c
index b9e79e8c7226..c4d472b7f1b4 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/kernel/reboot.c
  *
diff --git a/kernel/resource.c b/kernel/resource.c
index 8c15f846e8ef..158f04ec1d4f 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *      linux/kernel/resource.c
  *
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index e3e3b979f9bd..1152259a4ca0 100644
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * sched_clock() for unstable CPU clocks
  *
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 102dfcf0a29a..874c427742a9 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  kernel/sched/core.c
  *
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index ba4a143bdcf3..2305ce89a26c 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Simple CPU accounting cgroup controller
  */
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index f5516bae0c1b..80940939b733 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Generic entry points for the idle threads and
  * implementation of the idle task scheduling class.
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 687302051a27..123ea07a3f3b 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  Housekeeping management. Manage the targets for routine code that can run on
  *  any CPU: unbound workqueues, timers, kthreads and any offloadable work.
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index 6eb1f8efd221..fa0f9adfb752 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Generic waiting primitives.
  *
diff --git a/kernel/sched/wait_bit.c b/kernel/sched/wait_bit.c
index c67c6d24adc2..45eba18a2898 100644
--- a/kernel/sched/wait_bit.c
+++ b/kernel/sched/wait_bit.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * The implementation of the wait_bit*() and related waiting APIs:
  */
diff --git a/kernel/signal.c b/kernel/signal.c
index a1eb44dc9ff5..d7b9d14ac80d 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/kernel/signal.c
  *
diff --git a/kernel/smp.c b/kernel/smp.c
index f4cf1b0bb3b8..d155374632eb 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Generic helpers for smp ipi calls
  *
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index c230c2dd48e1..2efe1e206167 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Common SMP CPU bringup/teardown functions
  */
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 27bafc1e271e..5667f1da3ede 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * kernel/stacktrace.c
  *
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 7231fb5953fc..2b5a6754646f 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * kernel/stop_machine.c
  *
@@ -5,8 +6,6 @@
  * Copyright (C) 2008, 2005     Rusty Russell rusty@rustcorp.com.au
  * Copyright (C) 2010           SUSE Linux Products GmbH
  * Copyright (C) 2010           Tejun Heo <tj@kernel.org>
- *
- * This file is released under the GPLv2 and any later version.
  */
 #include <linux/completion.h>
 #include <linux/cpu.h>
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 943c89178e3d..7d1008be6173 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * sysctl.c: General linux system control interface
  *
diff --git a/kernel/test_kprobes.c b/kernel/test_kprobes.c
index 7bca480151b0..76c997fdbc9d 100644
--- a/kernel/test_kprobes.c
+++ b/kernel/test_kprobes.c
@@ -1,17 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * test_kprobes.c - simple sanity test for *probes
  *
  * Copyright IBM Corp. 2008
- *
- * 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 would 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.
  */
 
 #define pr_fmt(fmt) "Kprobe smoke test: " fmt
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index e2c038d6c13c..fcc42353f125 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Timer subsystem related configuration options
 #
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 5d965cef6c77..564e5fdb025f 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Architectures that offer an FUNCTION_TRACER implementation should
 #  select HAVE_FUNCTION_TRACER:
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index b496ffdf5f36..f92d6ad5e080 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1297,7 +1297,8 @@ int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id,
 }
 
 #ifdef CONFIG_MODULES
-int bpf_event_notify(struct notifier_block *nb, unsigned long op, void *module)
+static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
+                            void *module)
 {
         struct bpf_trace_module *btm, *tmp;
         struct module *mod = module;
@@ -1336,7 +1337,7 @@ static struct notifier_block bpf_module_nb = {
         .notifier_call = bpf_event_notify,
 };
 
-int __init bpf_event_init(void)
+static int __init bpf_event_init(void)
 {
         register_module_notifier(&bpf_module_nb);
         return 0;
diff --git a/kernel/umh.c b/kernel/umh.c
index d937cbad903a..7f255b5a8845 100644
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * umh - the kernel usermode helper
  */
diff --git a/kernel/up.c b/kernel/up.c
index ff536f9cc8a2..483c9962c999 100644
--- a/kernel/up.c
+++ b/kernel/up.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Uniprocessor-only support functions.  The counterpart to kernel/smp.c
  */
diff --git a/kernel/user-return-notifier.c b/kernel/user-return-notifier.c
index 9586b670a5b2..870ecd7c63ed 100644
--- a/kernel/user-return-notifier.c
+++ b/kernel/user-return-notifier.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 
 #include <linux/user-return-notifier.h>
 #include <linux/percpu.h>
diff --git a/kernel/user.c b/kernel/user.c
index 88b834f0eebc..78b17e36e705 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * The "user cache".
  *
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 9657315405de..95aea04ff722 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * kernel/workqueue.c - generic async execution with shared worker pool
  *