Merge branch 'linus' into tracing/urgent

Merge reason: Merge up to almost-rc6 to pick up latest perfcounters
              (on which we'll queue up a dependent fix)

Signed-off-by: Ingo Molnar <mingo@elte.hu>

12 files changed, 254 insertions, 116 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3737a682cdf5..b6eadfe30e7b 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -47,6 +47,7 @@
 #include <linux/hash.h>
 #include <linux/namei.h>
 #include <linux/smp_lock.h>
+#include <linux/pid_namespace.h>
 
 #include <asm/atomic.h>
 
@@ -734,16 +735,28 @@ static void cgroup_d_remove_dir(struct dentry *dentry)
  * reference to css->refcnt. In general, this refcnt is expected to goes down
  * to zero, soon.
  *
- * CGRP_WAIT_ON_RMDIR flag is modified under cgroup's inode->i_mutex;
+ * CGRP_WAIT_ON_RMDIR flag is set under cgroup's inode->i_mutex;
  */
 DECLARE_WAIT_QUEUE_HEAD(cgroup_rmdir_waitq);
 
-static void cgroup_wakeup_rmdir_waiters(const struct cgroup *cgrp)
+static void cgroup_wakeup_rmdir_waiter(struct cgroup *cgrp)
 {
-	if (unlikely(test_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags)))
+	if (unlikely(test_and_clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags)))
 		wake_up_all(&cgroup_rmdir_waitq);
 }
 
+void cgroup_exclude_rmdir(struct cgroup_subsys_state *css)
+{
+	css_get(css);
+}
+
+void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css)
+{
+	cgroup_wakeup_rmdir_waiter(css->cgroup);
+	css_put(css);
+}
+
+
 static int rebind_subsystems(struct cgroupfs_root *root,
 			      unsigned long final_bits)
 {
@@ -960,6 +973,7 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
 	INIT_LIST_HEAD(&cgrp->children);
 	INIT_LIST_HEAD(&cgrp->css_sets);
 	INIT_LIST_HEAD(&cgrp->release_list);
+	INIT_LIST_HEAD(&cgrp->pids_list);
 	init_rwsem(&cgrp->pids_mutex);
 }
 static void init_cgroup_root(struct cgroupfs_root *root)
@@ -1357,7 +1371,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
 	 * wake up rmdir() waiter. the rmdir should fail since the cgroup
 	 * is no longer empty.
 	 */
-	cgroup_wakeup_rmdir_waiters(cgrp);
+	cgroup_wakeup_rmdir_waiter(cgrp);
 	return 0;
 }
 
@@ -2201,12 +2215,30 @@ err:
 	return ret;
 }
 
+/*
+ * Cache pids for all threads in the same pid namespace that are
+ * opening the same "tasks" file.
+ */
+struct cgroup_pids {
+	/* The node in cgrp->pids_list */
+	struct list_head list;
+	/* The cgroup those pids belong to */
+	struct cgroup *cgrp;
+	/* The namepsace those pids belong to */
+	struct pid_namespace *ns;
+	/* Array of process ids in the cgroup */
+	pid_t *tasks_pids;
+	/* How many files are using the this tasks_pids array */
+	int use_count;
+	/* Length of the current tasks_pids array */
+	int length;
+};
+
 static int cmppid(const void *a, const void *b)
 {
 	return *(pid_t *)a - *(pid_t *)b;
 }
 
-
 /*
  * seq_file methods for the "tasks" file. The seq_file position is the
  * next pid to display; the seq_file iterator is a pointer to the pid
@@ -2221,45 +2253,47 @@ static void *cgroup_tasks_start(struct seq_file *s, loff_t *pos)
 	 * after a seek to the start). Use a binary-search to find the
 	 * next pid to display, if any
 	 */
-	struct cgroup *cgrp = s->private;
+	struct cgroup_pids *cp = s->private;
+	struct cgroup *cgrp = cp->cgrp;
 	int index = 0, pid = *pos;
 	int *iter;
 
 	down_read(&cgrp->pids_mutex);
 	if (pid) {
-		int end = cgrp->pids_length;
+		int end = cp->length;
 
 		while (index < end) {
 			int mid = (index + end) / 2;
-			if (cgrp->tasks_pids[mid] == pid) {
+			if (cp->tasks_pids[mid] == pid) {
 				index = mid;
 				break;
-			} else if (cgrp->tasks_pids[mid] <= pid)
+			} else if (cp->tasks_pids[mid] <= pid)
 				index = mid + 1;
 			else
 				end = mid;
 		}
 	}
 	/* If we're off the end of the array, we're done */
-	if (index >= cgrp->pids_length)
+	if (index >= cp->length)
 		return NULL;
 	/* Update the abstract position to be the actual pid that we found */
-	iter = cgrp->tasks_pids + index;
+	iter = cp->tasks_pids + index;
 	*pos = *iter;
 	return iter;
 }
 
 static void cgroup_tasks_stop(struct seq_file *s, void *v)
 {
-	struct cgroup *cgrp = s->private;
+	struct cgroup_pids *cp = s->private;
+	struct cgroup *cgrp = cp->cgrp;
 	up_read(&cgrp->pids_mutex);
 }
 
 static void *cgroup_tasks_next(struct seq_file *s, void *v, loff_t *pos)
 {
-	struct cgroup *cgrp = s->private;
+	struct cgroup_pids *cp = s->private;
 	int *p = v;
-	int *end = cgrp->tasks_pids + cgrp->pids_length;
+	int *end = cp->tasks_pids + cp->length;
 
 	/*
 	 * Advance to the next pid in the array. If this goes off the
@@ -2286,26 +2320,33 @@ static struct seq_operations cgroup_tasks_seq_operations = {
 	.show = cgroup_tasks_show,
 };
 
-static void release_cgroup_pid_array(struct cgroup *cgrp)
+static void release_cgroup_pid_array(struct cgroup_pids *cp)
 {
+	struct cgroup *cgrp = cp->cgrp;
+
 	down_write(&cgrp->pids_mutex);
-	BUG_ON(!cgrp->pids_use_count);
-	if (!--cgrp->pids_use_count) {
-		kfree(cgrp->tasks_pids);
-		cgrp->tasks_pids = NULL;
-		cgrp->pids_length = 0;
+	BUG_ON(!cp->use_count);
+	if (!--cp->use_count) {
+		list_del(&cp->list);
+		put_pid_ns(cp->ns);
+		kfree(cp->tasks_pids);
+		kfree(cp);
 	}
 	up_write(&cgrp->pids_mutex);
 }
 
 static int cgroup_tasks_release(struct inode *inode, struct file *file)
 {
-	struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
+	struct seq_file *seq;
+	struct cgroup_pids *cp;
 
 	if (!(file->f_mode & FMODE_READ))
 		return 0;
 
-	release_cgroup_pid_array(cgrp);
+	seq = file->private_data;
+	cp = seq->private;
+
+	release_cgroup_pid_array(cp);
 	return seq_release(inode, file);
 }
 
@@ -2324,6 +2365,8 @@ static struct file_operations cgroup_tasks_operations = {
 static int cgroup_tasks_open(struct inode *unused, struct file *file)
 {
 	struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
+	struct pid_namespace *ns = current->nsproxy->pid_ns;
+	struct cgroup_pids *cp;
 	pid_t *pidarray;
 	int npids;
 	int retval;
@@ -2350,20 +2393,37 @@ static int cgroup_tasks_open(struct inode *unused, struct file *file)
 	 * array if necessary
 	 */
 	down_write(&cgrp->pids_mutex);
-	kfree(cgrp->tasks_pids);
-	cgrp->tasks_pids = pidarray;
-	cgrp->pids_length = npids;
-	cgrp->pids_use_count++;
+
+	list_for_each_entry(cp, &cgrp->pids_list, list) {
+		if (ns == cp->ns)
+			goto found;
+	}
+
+	cp = kzalloc(sizeof(*cp), GFP_KERNEL);
+	if (!cp) {
+		up_write(&cgrp->pids_mutex);
+		kfree(pidarray);
+		return -ENOMEM;
+	}
+	cp->cgrp = cgrp;
+	cp->ns = ns;
+	get_pid_ns(ns);
+	list_add(&cp->list, &cgrp->pids_list);
+found:
+	kfree(cp->tasks_pids);
+	cp->tasks_pids = pidarray;
+	cp->length = npids;
+	cp->use_count++;
 	up_write(&cgrp->pids_mutex);
 
 	file->f_op = &cgroup_tasks_operations;
 
 	retval = seq_open(file, &cgroup_tasks_seq_operations);
 	if (retval) {
-		release_cgroup_pid_array(cgrp);
+		release_cgroup_pid_array(cp);
 		return retval;
 	}
-	((struct seq_file *)file->private_data)->private = cgrp;
+	((struct seq_file *)file->private_data)->private = cp;
 	return 0;
 }
 
@@ -2696,33 +2756,42 @@ again:
 	mutex_unlock(&cgroup_mutex);
 
 	/*
+	 * In general, subsystem has no css->refcnt after pre_destroy(). But
+	 * in racy cases, subsystem may have to get css->refcnt after
+	 * pre_destroy() and it makes rmdir return with -EBUSY. This sometimes
+	 * make rmdir return -EBUSY too often. To avoid that, we use waitqueue
+	 * for cgroup's rmdir. CGRP_WAIT_ON_RMDIR is for synchronizing rmdir
+	 * and subsystem's reference count handling. Please see css_get/put
+	 * and css_tryget() and cgroup_wakeup_rmdir_waiter() implementation.
+	 */
+	set_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags);
+
+	/*
 	 * Call pre_destroy handlers of subsys. Notify subsystems
 	 * that rmdir() request comes.
 	 */
 	ret = cgroup_call_pre_destroy(cgrp);
-	if (ret)
+	if (ret) {
+		clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags);
 		return ret;
+	}
 
 	mutex_lock(&cgroup_mutex);
 	parent = cgrp->parent;
 	if (atomic_read(&cgrp->count) || !list_empty(&cgrp->children)) {
+		clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags);
 		mutex_unlock(&cgroup_mutex);
 		return -EBUSY;
 	}
-	/*
-	 * css_put/get is provided for subsys to grab refcnt to css. In typical
-	 * case, subsystem has no reference after pre_destroy(). But, under
-	 * hierarchy management, some *temporal* refcnt can be hold.
-	 * To avoid returning -EBUSY to a user, waitqueue is used. If subsys
-	 * is really busy, it should return -EBUSY at pre_destroy(). wake_up
-	 * is called when css_put() is called and refcnt goes down to 0.
-	 */
-	set_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags);
 	prepare_to_wait(&cgroup_rmdir_waitq, &wait, TASK_INTERRUPTIBLE);
-
 	if (!cgroup_clear_css_refs(cgrp)) {
 		mutex_unlock(&cgroup_mutex);
-		schedule();
+		/*
+		 * Because someone may call cgroup_wakeup_rmdir_waiter() before
+		 * prepare_to_wait(), we need to check this flag.
+		 */
+		if (test_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags))
+			schedule();
 		finish_wait(&cgroup_rmdir_waitq, &wait);
 		clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags);
 		if (signal_pending(current))
@@ -3294,7 +3363,7 @@ void __css_put(struct cgroup_subsys_state *css)
 			set_bit(CGRP_RELEASABLE, &cgrp->flags);
 			check_for_release(cgrp);
 		}
-		cgroup_wakeup_rmdir_waiters(cgrp);
+		cgroup_wakeup_rmdir_waiter(cgrp);
 	}
 	rcu_read_unlock();
 }
diff --git a/kernel/fork.c b/kernel/fork.c
index 9b42695f0d14..021e1138556e 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -426,6 +426,7 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
 	init_rwsem(&mm->mmap_sem);
 	INIT_LIST_HEAD(&mm->mmlist);
 	mm->flags = (current->mm) ? current->mm->flags : default_dump_filter;
+	mm->oom_adj = (current->mm) ? current->mm->oom_adj : 0;
 	mm->core_state = NULL;
 	mm->nr_ptes = 0;
 	set_mm_counter(mm, file_rss, 0);
@@ -567,18 +568,18 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 	 * the value intact in a core dump, and to save the unnecessary
 	 * trouble otherwise.  Userland only wants this done for a sys_exit.
 	 */
-	if (tsk->clear_child_tid
-	    && !(tsk->flags & PF_SIGNALED)
-	    && atomic_read(&mm->mm_users) > 1) {
-		u32 __user * tidptr = tsk->clear_child_tid;
+	if (tsk->clear_child_tid) {
+		if (!(tsk->flags & PF_SIGNALED) &&
+		    atomic_read(&mm->mm_users) > 1) {
+			/*
+			 * We don't check the error code - if userspace has
+			 * not set up a proper pointer then tough luck.
+			 */
+			put_user(0, tsk->clear_child_tid);
+			sys_futex(tsk->clear_child_tid, FUTEX_WAKE,
+					1, NULL, NULL, 0);
+		}
 		tsk->clear_child_tid = NULL;
-
-		/*
-		 * We don't check the error code - if userspace has
-		 * not set up a proper pointer then tough luck.
-		 */
-		put_user(0, tidptr);
-		sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0);
 	}
 }
 
@@ -1268,6 +1269,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	write_unlock_irq(&tasklist_lock);
 	proc_fork_connector(p);
 	cgroup_post_fork(p);
+	perf_counter_fork(p);
 	return p;
 
 bad_fork_free_pid:
@@ -1409,9 +1411,6 @@ long do_fork(unsigned long clone_flags,
 			init_completion(&vfork);
 		}
 
-		if (!(clone_flags & CLONE_THREAD))
-			perf_counter_fork(p);
-
 		audit_finish_fork(p);
 		tracehook_report_clone(regs, clone_flags, nr, p);
 
diff --git a/kernel/kexec.c b/kernel/kexec.c
index ae1c35201cc8..f336e2107f98 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1228,7 +1228,7 @@ static int __init parse_crashkernel_mem(char 			*cmdline,
 	} while (*cur++ == ',');
 
 	if (*crash_size > 0) {
-		while (*cur != ' ' && *cur != '@')
+		while (*cur && *cur != ' ' && *cur != '@')
 			cur++;
 		if (*cur == '@') {
 			cur++;
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 16b5739c516a..0540948e29ab 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -694,7 +694,7 @@ int __kprobes register_kprobe(struct kprobe *p)
 	p->addr = addr;
 
 	preempt_disable();
-	if (!__kernel_text_address((unsigned long) p->addr) ||
+	if (!kernel_text_address((unsigned long) p->addr) ||
 	    in_kprobes_functions((unsigned long) p->addr)) {
 		preempt_enable();
 		return -EINVAL;
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 950931041954..673c1aaf7332 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -42,6 +42,7 @@ static int perf_overcommit __read_mostly = 1;
 static atomic_t nr_counters __read_mostly;
 static atomic_t nr_mmap_counters __read_mostly;
 static atomic_t nr_comm_counters __read_mostly;
+static atomic_t nr_task_counters __read_mostly;
 
 /*
  * perf counter paranoia level:
@@ -1103,7 +1104,7 @@ static void perf_counter_sync_stat(struct perf_counter_context *ctx,
 		__perf_counter_sync_stat(counter, next_counter);
 
 		counter = list_next_entry(counter, event_entry);
-		next_counter = list_next_entry(counter, event_entry);
+		next_counter = list_next_entry(next_counter, event_entry);
 	}
 }
 
@@ -1654,6 +1655,8 @@ static void free_counter(struct perf_counter *counter)
 			atomic_dec(&nr_mmap_counters);
 		if (counter->attr.comm)
 			atomic_dec(&nr_comm_counters);
+		if (counter->attr.task)
+			atomic_dec(&nr_task_counters);
 	}
 
 	if (counter->destroy)
@@ -1688,6 +1691,18 @@ static int perf_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
+static u64 perf_counter_read_tree(struct perf_counter *counter)
+{
+	struct perf_counter *child;
+	u64 total = 0;
+
+	total += perf_counter_read(counter);
+	list_for_each_entry(child, &counter->child_list, child_list)
+		total += perf_counter_read(child);
+
+	return total;
+}
+
 /*
  * Read the performance counter - simple non blocking version for now
  */
@@ -1707,7 +1722,7 @@ perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count)
 
 	WARN_ON_ONCE(counter->ctx->parent_ctx);
 	mutex_lock(&counter->child_mutex);
-	values[0] = perf_counter_read(counter);
+	values[0] = perf_counter_read_tree(counter);
 	n = 1;
 	if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
 		values[n++] = counter->total_time_enabled +
@@ -2819,10 +2834,12 @@ perf_counter_read_event(struct perf_counter *counter,
 }
 
 /*
- * fork tracking
+ * task tracking -- fork/exit
+ *
+ * enabled by: attr.comm | attr.mmap | attr.task
  */
 
-struct perf_fork_event {
+struct perf_task_event {
 	struct task_struct	*task;
 
 	struct {
@@ -2830,37 +2847,42 @@ struct perf_fork_event {
 
 		u32				pid;
 		u32				ppid;
+		u32				tid;
+		u32				ptid;
 	} event;
 };
 
-static void perf_counter_fork_output(struct perf_counter *counter,
-				     struct perf_fork_event *fork_event)
+static void perf_counter_task_output(struct perf_counter *counter,
+				     struct perf_task_event *task_event)
 {
 	struct perf_output_handle handle;
-	int size = fork_event->event.header.size;
-	struct task_struct *task = fork_event->task;
+	int size = task_event->event.header.size;
+	struct task_struct *task = task_event->task;
 	int ret = perf_output_begin(&handle, counter, size, 0, 0);
 
 	if (ret)
 		return;
 
-	fork_event->event.pid = perf_counter_pid(counter, task);
-	fork_event->event.ppid = perf_counter_pid(counter, task->real_parent);
+	task_event->event.pid = perf_counter_pid(counter, task);
+	task_event->event.ppid = perf_counter_pid(counter, task->real_parent);
 
-	perf_output_put(&handle, fork_event->event);
+	task_event->event.tid = perf_counter_tid(counter, task);
+	task_event->event.ptid = perf_counter_tid(counter, task->real_parent);
+
+	perf_output_put(&handle, task_event->event);
 	perf_output_end(&handle);
 }
 
-static int perf_counter_fork_match(struct perf_counter *counter)
+static int perf_counter_task_match(struct perf_counter *counter)
 {
-	if (counter->attr.comm || counter->attr.mmap)
+	if (counter->attr.comm || counter->attr.mmap || counter->attr.task)
 		return 1;
 
 	return 0;
 }
 
-static void perf_counter_fork_ctx(struct perf_counter_context *ctx,
-				  struct perf_fork_event *fork_event)
+static void perf_counter_task_ctx(struct perf_counter_context *ctx,
+				  struct perf_task_event *task_event)
 {
 	struct perf_counter *counter;
 
@@ -2869,19 +2891,19 @@ static void perf_counter_fork_ctx(struct perf_counter_context *ctx,
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
-		if (perf_counter_fork_match(counter))
-			perf_counter_fork_output(counter, fork_event);
+		if (perf_counter_task_match(counter))
+			perf_counter_task_output(counter, task_event);
 	}
 	rcu_read_unlock();
 }
 
-static void perf_counter_fork_event(struct perf_fork_event *fork_event)
+static void perf_counter_task_event(struct perf_task_event *task_event)
 {
 	struct perf_cpu_context *cpuctx;
 	struct perf_counter_context *ctx;
 
 	cpuctx = &get_cpu_var(perf_cpu_context);
-	perf_counter_fork_ctx(&cpuctx->ctx, fork_event);
+	perf_counter_task_ctx(&cpuctx->ctx, task_event);
 	put_cpu_var(perf_cpu_context);
 
 	rcu_read_lock();
@@ -2891,32 +2913,40 @@ static void perf_counter_fork_event(struct perf_fork_event *fork_event)
 	 */
 	ctx = rcu_dereference(current->perf_counter_ctxp);
 	if (ctx)
-		perf_counter_fork_ctx(ctx, fork_event);
+		perf_counter_task_ctx(ctx, task_event);
 	rcu_read_unlock();
 }
 
-void perf_counter_fork(struct task_struct *task)
+static void perf_counter_task(struct task_struct *task, int new)
 {
-	struct perf_fork_event fork_event;
+	struct perf_task_event task_event;
 
 	if (!atomic_read(&nr_comm_counters) &&
-	    !atomic_read(&nr_mmap_counters))
+	    !atomic_read(&nr_mmap_counters) &&
+	    !atomic_read(&nr_task_counters))
 		return;
 
-	fork_event = (struct perf_fork_event){
+	task_event = (struct perf_task_event){
 		.task	= task,
 		.event  = {
 			.header = {
-				.type = PERF_EVENT_FORK,
+				.type = new ? PERF_EVENT_FORK : PERF_EVENT_EXIT,
 				.misc = 0,
-				.size = sizeof(fork_event.event),
+				.size = sizeof(task_event.event),
 			},
 			/* .pid  */
 			/* .ppid */
+			/* .tid  */
+			/* .ptid */
 		},
 	};
 
-	perf_counter_fork_event(&fork_event);
+	perf_counter_task_event(&task_event);
+}
+
+void perf_counter_fork(struct task_struct *task)
+{
+	perf_counter_task(task, 1);
 }
 
 /*
@@ -3875,6 +3905,8 @@ done:
 			atomic_inc(&nr_mmap_counters);
 		if (counter->attr.comm)
 			atomic_inc(&nr_comm_counters);
+		if (counter->attr.task)
+			atomic_inc(&nr_task_counters);
 	}
 
 	return counter;
@@ -4236,8 +4268,10 @@ void perf_counter_exit_task(struct task_struct *child)
 	struct perf_counter_context *child_ctx;
 	unsigned long flags;
 
-	if (likely(!child->perf_counter_ctxp))
+	if (likely(!child->perf_counter_ctxp)) {
+		perf_counter_task(child, 0);
 		return;
+	}
 
 	local_irq_save(flags);
 	/*
@@ -4255,15 +4289,22 @@ void perf_counter_exit_task(struct task_struct *child)
 	 * incremented the context's refcount before we do put_ctx below.
 	 */
 	spin_lock(&child_ctx->lock);
-	child->perf_counter_ctxp = NULL;
 	/*
 	 * If this context is a clone; unclone it so it can't get
 	 * swapped to another process while we're removing all
 	 * the counters from it.
 	 */
 	unclone_ctx(child_ctx);
-	spin_unlock(&child_ctx->lock);
-	local_irq_restore(flags);
+	spin_unlock_irqrestore(&child_ctx->lock, flags);
+
+	/*
+	 * Report the task dead after unscheduling the counters so that we
+	 * won't get any samples after PERF_EVENT_EXIT. We can however still
+	 * get a few PERF_EVENT_READ events.
+	 */
+	perf_counter_task(child, 0);
+
+	child->perf_counter_ctxp = NULL;
 
 	/*
 	 * We can recurse on the same lock type through:
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index 052ec4d195c7..d089d052c4a9 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -202,6 +202,12 @@ static int no_timer_create(struct k_itimer *new_timer)
 	return -EOPNOTSUPP;
 }
 
+static int no_nsleep(const clockid_t which_clock, int flags,
+		     struct timespec *tsave, struct timespec __user *rmtp)
+{
+	return -EOPNOTSUPP;
+}
+
 /*
  * Return nonzero if we know a priori this clockid_t value is bogus.
  */
@@ -254,6 +260,7 @@ static __init int init_posix_timers(void)
 		.clock_get = posix_get_monotonic_raw,
 		.clock_set = do_posix_clock_nosettime,
 		.timer_create = no_timer_create,
+		.nsleep = no_nsleep,
 	};
 
 	register_posix_clock(CLOCK_REALTIME, &clock_realtime);
diff --git a/kernel/sched_cpupri.c b/kernel/sched_cpupri.c
index e6c251790dde..d014efbf947a 100644
--- a/kernel/sched_cpupri.c
+++ b/kernel/sched_cpupri.c
@@ -81,8 +81,21 @@ int cpupri_find(struct cpupri *cp, struct task_struct *p,
 		if (cpumask_any_and(&p->cpus_allowed, vec->mask) >= nr_cpu_ids)
 			continue;
 
-		if (lowest_mask)
+		if (lowest_mask) {
 			cpumask_and(lowest_mask, &p->cpus_allowed, vec->mask);
+
+			/*
+			 * We have to ensure that we have at least one bit
+			 * still set in the array, since the map could have
+			 * been concurrently emptied between the first and
+			 * second reads of vec->mask.  If we hit this
+			 * condition, simply act as though we never hit this
+			 * priority level and continue on.
+			 */
+			if (cpumask_any(lowest_mask) >= nr_cpu_ids)
+				continue;
+		}
+
 		return 1;
 	}
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 9ffb2b2ceba4..652e8bdef9aa 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -611,9 +611,13 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 #ifdef CONFIG_SCHEDSTATS
+	struct task_struct *tsk = NULL;
+
+	if (entity_is_task(se))
+		tsk = task_of(se);
+
 	if (se->sleep_start) {
 		u64 delta = rq_of(cfs_rq)->clock - se->sleep_start;
-		struct task_struct *tsk = task_of(se);
 
 		if ((s64)delta < 0)
 			delta = 0;
@@ -624,11 +628,11 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
 		se->sleep_start = 0;
 		se->sum_sleep_runtime += delta;
 
-		account_scheduler_latency(tsk, delta >> 10, 1);
+		if (tsk)
+			account_scheduler_latency(tsk, delta >> 10, 1);
 	}
 	if (se->block_start) {
 		u64 delta = rq_of(cfs_rq)->clock - se->block_start;
-		struct task_struct *tsk = task_of(se);
 
 		if ((s64)delta < 0)
 			delta = 0;
@@ -639,17 +643,19 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
 		se->block_start = 0;
 		se->sum_sleep_runtime += delta;
 
-		/*
-		 * Blocking time is in units of nanosecs, so shift by 20 to
-		 * get a milliseconds-range estimation of the amount of
-		 * time that the task spent sleeping:
-		 */
-		if (unlikely(prof_on == SLEEP_PROFILING)) {
-
-			profile_hits(SLEEP_PROFILING, (void *)get_wchan(tsk),
-				     delta >> 20);
+		if (tsk) {
+			/*
+			 * Blocking time is in units of nanosecs, so shift by
+			 * 20 to get a milliseconds-range estimation of the
+			 * amount of time that the task spent sleeping:
+			 */
+			if (unlikely(prof_on == SLEEP_PROFILING)) {
+				profile_hits(SLEEP_PROFILING,
+						(void *)get_wchan(tsk),
+						delta >> 20);
+			}
+			account_scheduler_latency(tsk, delta >> 10, 0);
 		}
-		account_scheduler_latency(tsk, delta >> 10, 0);
 	}
 #endif
 }
diff --git a/kernel/signal.c b/kernel/signal.c
index ccf1ceedaebe..64c5deeaca5d 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2454,11 +2454,9 @@ do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long s
 	stack_t oss;
 	int error;
 
-	if (uoss) {
-		oss.ss_sp = (void __user *) current->sas_ss_sp;
-		oss.ss_size = current->sas_ss_size;
-		oss.ss_flags = sas_ss_flags(sp);
-	}
+	oss.ss_sp = (void __user *) current->sas_ss_sp;
+	oss.ss_size = current->sas_ss_size;
+	oss.ss_flags = sas_ss_flags(sp);
 
 	if (uss) {
 		void __user *ss_sp;
@@ -2466,10 +2464,12 @@ do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long s
 		int ss_flags;
 
 		error = -EFAULT;
-		if (!access_ok(VERIFY_READ, uss, sizeof(*uss))
-		    || __get_user(ss_sp, &uss->ss_sp)
-		    || __get_user(ss_flags, &uss->ss_flags)
-		    || __get_user(ss_size, &uss->ss_size))
+		if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
+			goto out;
+		error = __get_user(ss_sp, &uss->ss_sp) |
+			__get_user(ss_flags, &uss->ss_flags) |
+			__get_user(ss_size, &uss->ss_size);
+		if (error)
 			goto out;
 
 		error = -EPERM;
@@ -2501,13 +2501,16 @@ do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long s
 		current->sas_ss_size = ss_size;
 	}
 
+	error = 0;
 	if (uoss) {
 		error = -EFAULT;
-		if (copy_to_user(uoss, &oss, sizeof(oss)))
+		if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
 			goto out;
+		error = __put_user(oss.ss_sp, &uoss->ss_sp) |
+			__put_user(oss.ss_size, &uoss->ss_size) |
+			__put_user(oss.ss_flags, &uoss->ss_flags);
 	}
 
-	error = 0;
 out:
 	return error;
 }
diff --git a/kernel/smp.c b/kernel/smp.c
index ad63d8501207..94188b8ecc33 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -57,7 +57,7 @@ hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
 			return NOTIFY_BAD;
 		break;
 
-#ifdef CONFIG_CPU_HOTPLUG
+#ifdef CONFIG_HOTPLUG_CPU
 	case CPU_UP_CANCELED:
 	case CPU_UP_CANCELED_FROZEN:
 
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c
index 5b5895afecfe..11ba5bb4ed0a 100644
--- a/kernel/trace/trace_event_profile.c
+++ b/kernel/trace/trace_event_profile.c
@@ -14,7 +14,7 @@ int ftrace_profile_enable(int event_id)
 
 	mutex_lock(&event_mutex);
 	list_for_each_entry(event, &ftrace_events, list) {
-		if (event->id == event_id) {
+		if (event->id == event_id && event->profile_enable) {
 			ret = event->profile_enable(event);
 			break;
 		}
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 23d2972b22d6..e75276a49cf5 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -940,7 +940,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
 		entry = trace_create_file("enable", 0644, call->dir, call,
 					  enable);
 
-	if (call->id)
+	if (call->id && call->profile_enable)
 		entry = trace_create_file("id", 0444, call->dir, call,
 					  id);