Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:

 - a few block updates that fell in my lap

 - lib/ updates

 - checkpatch

 - autofs

 - ipc

 - a ton of misc other things

* emailed patches from Andrew Morton <[email protected]>: (100 commits)
  mm: split gfp_mask and mapping flags into separate fields
  fs: use mapping_set_error instead of opencoded set_bit
  treewide: remove redundant #include <linux/kconfig.h>
  hung_task: allow hung_task_panic when hung_task_warnings is 0
  kthread: add kerneldoc for kthread_create()
  kthread: better support freezable kthread workers
  kthread: allow to modify delayed kthread work
  kthread: allow to cancel kthread work
  kthread: initial support for delayed kthread work
  kthread: detect when a kthread work is used by more workers
  kthread: add kthread_destroy_worker()
  kthread: add kthread_create_worker*()
  kthread: allow to call __kthread_create_on_node() with va_list args
  kthread/smpboot: do not park in kthread_create_on_cpu()
  kthread: kthread worker API cleanup
  kthread: rename probe_kthread_data() to kthread_probe_data()
  scripts/tags.sh: enable code completion in VIM
  mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping
  kdump, vmcoreinfo: report memory sections virtual addresses
  ipc/sem.c: add cond_resched in exit_sme
  ...

1 files changed, 180 insertions, 0 deletions

diff --git a/tools/testing/radix-tree/iteration_check.c b/tools/testing/radix-tree/iteration_check.c
new file mode 100644
index 000000000000..9adb8e7415a6
--- /dev/null
+++ b/tools/testing/radix-tree/iteration_check.c
@@ -0,0 +1,180 @@
+/*
+ * iteration_check.c: test races having to do with radix tree iteration
+ * Copyright (c) 2016 Intel Corporation
+ * Author: Ross Zwisler <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+#include <linux/radix-tree.h>
+#include <pthread.h>
+#include "test.h"
+
+#define NUM_THREADS 4
+#define TAG 0
+static pthread_mutex_t tree_lock = PTHREAD_MUTEX_INITIALIZER;
+static pthread_t threads[NUM_THREADS];
+RADIX_TREE(tree, GFP_KERNEL);
+bool test_complete;
+
+/* relentlessly fill the tree with tagged entries */
+static void *add_entries_fn(void *arg)
+{
+	int pgoff;
+
+	while (!test_complete) {
+		for (pgoff = 0; pgoff < 100; pgoff++) {
+			pthread_mutex_lock(&tree_lock);
+			if (item_insert(&tree, pgoff) == 0)
+				item_tag_set(&tree, pgoff, TAG);
+			pthread_mutex_unlock(&tree_lock);
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * Iterate over the tagged entries, doing a radix_tree_iter_retry() as we find
+ * things that have been removed and randomly resetting our iteration to the
+ * next chunk with radix_tree_iter_next().  Both radix_tree_iter_retry() and
+ * radix_tree_iter_next() cause radix_tree_next_slot() to be called with a
+ * NULL 'slot' variable.
+ */
+static void *tagged_iteration_fn(void *arg)
+{
+	struct radix_tree_iter iter;
+	void **slot;
+
+	while (!test_complete) {
+		rcu_read_lock();
+		radix_tree_for_each_tagged(slot, &tree, &iter, 0, TAG) {
+			void *entry;
+			int i;
+
+			/* busy wait to let removals happen */
+			for (i = 0; i < 1000000; i++)
+				;
+
+			entry = radix_tree_deref_slot(slot);
+			if (unlikely(!entry))
+				continue;
+
+			if (radix_tree_deref_retry(entry)) {
+				slot = radix_tree_iter_retry(&iter);
+				continue;
+			}
+
+			if (rand() % 50 == 0)
+				slot = radix_tree_iter_next(&iter);
+		}
+		rcu_read_unlock();
+	}
+
+	return NULL;
+}
+
+/*
+ * Iterate over the entries, doing a radix_tree_iter_retry() as we find things
+ * that have been removed and randomly resetting our iteration to the next
+ * chunk with radix_tree_iter_next().  Both radix_tree_iter_retry() and
+ * radix_tree_iter_next() cause radix_tree_next_slot() to be called with a
+ * NULL 'slot' variable.
+ */
+static void *untagged_iteration_fn(void *arg)
+{
+	struct radix_tree_iter iter;
+	void **slot;
+
+	while (!test_complete) {
+		rcu_read_lock();
+		radix_tree_for_each_slot(slot, &tree, &iter, 0) {
+			void *entry;
+			int i;
+
+			/* busy wait to let removals happen */
+			for (i = 0; i < 1000000; i++)
+				;
+
+			entry = radix_tree_deref_slot(slot);
+			if (unlikely(!entry))
+				continue;
+
+			if (radix_tree_deref_retry(entry)) {
+				slot = radix_tree_iter_retry(&iter);
+				continue;
+			}
+
+			if (rand() % 50 == 0)
+				slot = radix_tree_iter_next(&iter);
+		}
+		rcu_read_unlock();
+	}
+
+	return NULL;
+}
+
+/*
+ * Randomly remove entries to help induce radix_tree_iter_retry() calls in the
+ * two iteration functions.
+ */
+static void *remove_entries_fn(void *arg)
+{
+	while (!test_complete) {
+		int pgoff;
+
+		pgoff = rand() % 100;
+
+		pthread_mutex_lock(&tree_lock);
+		item_delete(&tree, pgoff);
+		pthread_mutex_unlock(&tree_lock);
+	}
+
+	return NULL;
+}
+
+/* This is a unit test for a bug found by the syzkaller tester */
+void iteration_test(void)
+{
+	int i;
+
+	printf("Running iteration tests for 10 seconds\n");
+
+	srand(time(0));
+	test_complete = false;
+
+	if (pthread_create(&threads[0], NULL, tagged_iteration_fn, NULL)) {
+		perror("pthread_create");
+		exit(1);
+	}
+	if (pthread_create(&threads[1], NULL, untagged_iteration_fn, NULL)) {
+		perror("pthread_create");
+		exit(1);
+	}
+	if (pthread_create(&threads[2], NULL, add_entries_fn, NULL)) {
+		perror("pthread_create");
+		exit(1);
+	}
+	if (pthread_create(&threads[3], NULL, remove_entries_fn, NULL)) {
+		perror("pthread_create");
+		exit(1);
+	}
+
+	sleep(10);
+	test_complete = true;
+
+	for (i = 0; i < NUM_THREADS; i++) {
+		if (pthread_join(threads[i], NULL)) {
+			perror("pthread_join");
+			exit(1);
+		}
+	}
+
+	item_kill_tree(&tree);
+}