Merge 4.0-rc5 into tty-next

We want the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/cpuset.c

@@ -548,9 +548,6 @@ static void update_domain_attr_tree(struct sched_domain_attr *dattr,
 
 	rcu_read_lock();
 	cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
-		if (cp == root_cs)
-			continue;
-
 		/* skip the whole subtree if @cp doesn't have any CPU */
 		if (cpumask_empty(cp->cpus_allowed)) {
 			pos_css = css_rightmost_descendant(pos_css);
@@ -873,7 +870,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
 		 * If it becomes empty, inherit the effective mask of the
 		 * parent, which is guaranteed to have some CPUs.
 		 */
-		if (cpumask_empty(new_cpus))
+		if (cgroup_on_dfl(cp->css.cgroup) && cpumask_empty(new_cpus))
 			cpumask_copy(new_cpus, parent->effective_cpus);
 
 		/* Skip the whole subtree if the cpumask remains the same. */
@@ -1129,7 +1126,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
 		 * If it becomes empty, inherit the effective mask of the
 		 * parent, which is guaranteed to have some MEMs.
 		 */
-		if (nodes_empty(*new_mems))
+		if (cgroup_on_dfl(cp->css.cgroup) && nodes_empty(*new_mems))
 			*new_mems = parent->effective_mems;
 
 		/* Skip the whole subtree if the nodemask remains the same. */
@@ -1979,7 +1976,9 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
 
 	spin_lock_irq(&callback_lock);
 	cs->mems_allowed = parent->mems_allowed;
+	cs->effective_mems = parent->mems_allowed;
 	cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
+	cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
 	spin_unlock_irq(&callback_lock);
 out_unlock:
 	mutex_unlock(&cpuset_mutex);

kernel/events/core.c

@@ -3591,7 +3591,7 @@ static void put_event(struct perf_event *event)
 	ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
 	WARN_ON_ONCE(ctx->parent_ctx);
 	perf_remove_from_context(event, true);
-	mutex_unlock(&ctx->mutex);
+	perf_event_ctx_unlock(event, ctx);
 
 	_free_event(event);
 }

kernel/livepatch/core.c

@@ -89,16 +89,28 @@ static bool klp_is_object_loaded(struct klp_object *obj)
 /* sets obj->mod if object is not vmlinux and module is found */
 static void klp_find_object_module(struct klp_object *obj)
 {
+	struct module *mod;
+
 	if (!klp_is_module(obj))
 		return;
 
 	mutex_lock(&module_mutex);
 	/*
-	 * We don't need to take a reference on the module here because we have
-	 * the klp_mutex, which is also taken by the module notifier.  This
-	 * prevents any module from unloading until we release the klp_mutex.
+	 * We do not want to block removal of patched modules and therefore
+	 * we do not take a reference here. The patches are removed by
+	 * a going module handler instead.
 	 */
-	obj->mod = find_module(obj->name);
+	mod = find_module(obj->name);
+	/*
+	 * Do not mess work of the module coming and going notifiers.
+	 * Note that the patch might still be needed before the going handler
+	 * is called. Module functions can be called even in the GOING state
+	 * until mod->exit() finishes. This is especially important for
+	 * patches that modify semantic of the functions.
+	 */
+	if (mod && mod->klp_alive)
+		obj->mod = mod;
+
 	mutex_unlock(&module_mutex);
 }
 
@@ -767,6 +779,7 @@ static int klp_init_object(struct klp_patch *patch, struct klp_object *obj)
 		return -EINVAL;
 
 	obj->state = KLP_DISABLED;
+	obj->mod = NULL;
 
 	klp_find_object_module(obj);
 
@@ -961,6 +974,15 @@ static int klp_module_notify(struct notifier_block *nb, unsigned long action,
 
 	mutex_lock(&klp_mutex);
 
+	/*
+	 * Each module has to know that the notifier has been called.
+	 * We never know what module will get patched by a new patch.
+	 */
+	if (action == MODULE_STATE_COMING)
+		mod->klp_alive = true;
+	else /* MODULE_STATE_GOING */
+		mod->klp_alive = false;
+
 	list_for_each_entry(patch, &klp_patches, list) {
 		for (obj = patch->objs; obj->funcs; obj++) {
 			if (!klp_is_module(obj) || strcmp(obj->name, mod->name))

kernel/module.c

@@ -56,7 +56,6 @@
 #include <linux/async.h>
 #include <linux/percpu.h>
 #include <linux/kmemleak.h>
-#include <linux/kasan.h>
 #include <linux/jump_label.h>
 #include <linux/pfn.h>
 #include <linux/bsearch.h>
@@ -1814,7 +1813,6 @@ static void unset_module_init_ro_nx(struct module *mod) { }
 void __weak module_memfree(void *module_region)
 {
 	vfree(module_region);
-	kasan_module_free(module_region);
 }
 
 void __weak module_arch_cleanup(struct module *mod)

kernel/trace/ftrace.c

@@ -1059,6 +1059,12 @@ static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 
 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static int ftrace_graph_active;
+#else
+# define ftrace_graph_active 0
+#endif
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 static struct ftrace_ops *removed_ops;
@@ -2041,8 +2047,12 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
 		if (!ftrace_rec_count(rec))
 			rec->flags = 0;
 		else
-			/* Just disable the record (keep REGS state) */
-			rec->flags &= ~FTRACE_FL_ENABLED;
+			/*
+			 * Just disable the record, but keep the ops TRAMP
+			 * and REGS states. The _EN flags must be disabled though.
+			 */
+			rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
+					FTRACE_FL_REGS_EN);
 	}
 
 	return FTRACE_UPDATE_MAKE_NOP;
@@ -2688,24 +2698,36 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
 
 static void ftrace_startup_sysctl(void)
 {
+	int command;
+
 	if (unlikely(ftrace_disabled))
 		return;
 
 	/* Force update next time */
 	saved_ftrace_func = NULL;
 	/* ftrace_start_up is true if we want ftrace running */
-	if (ftrace_start_up)
-		ftrace_run_update_code(FTRACE_UPDATE_CALLS);
+	if (ftrace_start_up) {
+		command = FTRACE_UPDATE_CALLS;
+		if (ftrace_graph_active)
+			command |= FTRACE_START_FUNC_RET;
+		ftrace_startup_enable(command);
+	}
 }
 
 static void ftrace_shutdown_sysctl(void)
 {
+	int command;
+
 	if (unlikely(ftrace_disabled))
 		return;
 
 	/* ftrace_start_up is true if ftrace is running */
-	if (ftrace_start_up)
-		ftrace_run_update_code(FTRACE_DISABLE_CALLS);
+	if (ftrace_start_up) {
+		command = FTRACE_DISABLE_CALLS;
+		if (ftrace_graph_active)
+			command |= FTRACE_STOP_FUNC_RET;
+		ftrace_run_update_code(command);
+	}
 }
 
 static cycle_t		ftrace_update_time;
@@ -5558,12 +5580,12 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 
 	if (ftrace_enabled) {
 
-		ftrace_startup_sysctl();
-
 		/* we are starting ftrace again */
 		if (ftrace_ops_list != &ftrace_list_end)
 			update_ftrace_function();
 
+		ftrace_startup_sysctl();
+
 	} else {
 		/* stopping ftrace calls (just send to ftrace_stub) */
 		ftrace_trace_function = ftrace_stub;
@@ -5590,8 +5612,6 @@ static struct ftrace_ops graph_ops = {
 	ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
 };
 
-static int ftrace_graph_active;
-
 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
 {
 	return 0;

kernel/workqueue.c

@@ -2728,19 +2728,57 @@ bool flush_work(struct work_struct *work)
 }
 EXPORT_SYMBOL_GPL(flush_work);
 
+struct cwt_wait {
+	wait_queue_t		wait;
+	struct work_struct	*work;
+};
+
+static int cwt_wakefn(wait_queue_t *wait, unsigned mode, int sync, void *key)
+{
+	struct cwt_wait *cwait = container_of(wait, struct cwt_wait, wait);
+
+	if (cwait->work != key)
+		return 0;
+	return autoremove_wake_function(wait, mode, sync, key);
+}
+
 static bool __cancel_work_timer(struct work_struct *work, bool is_dwork)
 {
+	static DECLARE_WAIT_QUEUE_HEAD(cancel_waitq);
 	unsigned long flags;
 	int ret;
 
 	do {
 		ret = try_to_grab_pending(work, is_dwork, &flags);
 		/*
-		 * If someone else is canceling, wait for the same event it
-		 * would be waiting for before retrying.
+		 * If someone else is already canceling, wait for it to
+		 * finish.  flush_work() doesn't work for PREEMPT_NONE
+		 * because we may get scheduled between @work's completion
+		 * and the other canceling task resuming and clearing
+		 * CANCELING - flush_work() will return false immediately
+		 * as @work is no longer busy, try_to_grab_pending() will
+		 * return -ENOENT as @work is still being canceled and the
+		 * other canceling task won't be able to clear CANCELING as
+		 * we're hogging the CPU.
+		 *
+		 * Let's wait for completion using a waitqueue.  As this
+		 * may lead to the thundering herd problem, use a custom
+		 * wake function which matches @work along with exclusive
+		 * wait and wakeup.
 		 */
-		if (unlikely(ret == -ENOENT))
-			flush_work(work);
+		if (unlikely(ret == -ENOENT)) {
+			struct cwt_wait cwait;
+
+			init_wait(&cwait.wait);
+			cwait.wait.func = cwt_wakefn;
+			cwait.work = work;
+
+			prepare_to_wait_exclusive(&cancel_waitq, &cwait.wait,
+						  TASK_UNINTERRUPTIBLE);
+			if (work_is_canceling(work))
+				schedule();
+			finish_wait(&cancel_waitq, &cwait.wait);
+		}
 	} while (unlikely(ret < 0));
 
 	/* tell other tasks trying to grab @work to back off */
@@ -2749,6 +2787,16 @@ static bool __cancel_work_timer(struct work_struct *work, bool is_dwork)
 
 	flush_work(work);
 	clear_work_data(work);
+
+	/*
+	 * Paired with prepare_to_wait() above so that either
+	 * waitqueue_active() is visible here or !work_is_canceling() is
+	 * visible there.
+	 */
+	smp_mb();
+	if (waitqueue_active(&cancel_waitq))
+		__wake_up(&cancel_waitq, TASK_NORMAL, 1, work);
+
 	return ret;
 }