6 files changed, 35 insertions, 15 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 36ea2b6..638711c 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -842,6 +842,7 @@ static void blk_add_trace_split(void *ignore,
 
 /**
  * blk_add_trace_remap - Add a trace for a remap operation
+ * @ignore:	trace callback data parameter (not used)
  * @q:		queue the io is for
  * @bio:	the source bio
  * @dev:	target device
@@ -873,6 +874,7 @@ static void blk_add_trace_remap(void *ignore,
 
 /**
  * blk_add_trace_rq_remap - Add a trace for a request-remap operation
+ * @ignore:	trace callback data parameter (not used)
  * @q:		queue the io is for
  * @rq:		the source request
  * @dev:	target device
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index c3d3cd9..28d0615 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1768,6 +1768,14 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
 	 * must fill the old tail_page with padding.
 	 */
 	if (tail >= BUF_PAGE_SIZE) {
+		/*
+		 * If the page was filled, then we still need
+		 * to update the real_end. Reset it to zero
+		 * and the reader will ignore it.
+		 */
+		if (tail == BUF_PAGE_SIZE)
+			tail_page->real_end = 0;
+
 		local_sub(length, &tail_page->write);
 		return;
 	}
@@ -3872,12 +3880,12 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
 	ret = read;
 
 	cpu_buffer->lost_events = 0;
+
+	commit = local_read(&bpage->commit);
 	/*
 	 * Set a flag in the commit field if we lost events
 	 */
 	if (missed_events) {
-		commit = local_read(&bpage->commit);
-
 		/* If there is room at the end of the page to save the
 		 * missed events, then record it there.
 		 */
@@ -3885,10 +3893,17 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
 			memcpy(&bpage->data[commit], &missed_events,
 			       sizeof(missed_events));
 			local_add(RB_MISSED_STORED, &bpage->commit);
+			commit += sizeof(missed_events);
 		}
 		local_add(RB_MISSED_EVENTS, &bpage->commit);
 	}
 
+	/*
+	 * This page may be off to user land. Zero it out here.
+	 */
+	if (commit < BUF_PAGE_SIZE)
+		memset(&bpage->data[commit], 0, BUF_PAGE_SIZE - commit);
+
  out_unlock:
 	spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3572714..644ab744 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3665,7 +3665,6 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 		     size_t count, loff_t *ppos)
 {
 	struct ftrace_buffer_info *info = filp->private_data;
-	unsigned int pos;
 	ssize_t ret;
 	size_t size;
 
@@ -3692,11 +3691,6 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 	if (ret < 0)
 		return 0;
 
-	pos = ring_buffer_page_len(info->spare);
-
-	if (pos < PAGE_SIZE)
-		memset(info->spare + pos, 0, PAGE_SIZE - pos);
-
 read:
 	size = PAGE_SIZE - info->read;
 	if (size > count)
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index cb6f365..e6f6588 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -116,7 +116,7 @@ int perf_trace_enable(struct perf_event *p_event)
 	if (WARN_ON_ONCE(!list))
 		return -EINVAL;
 
-	list = per_cpu_ptr(list, smp_processor_id());
+	list = this_cpu_ptr(list);
 	hlist_add_head_rcu(&p_event->hlist_entry, list);
 
 	return 0;
@@ -132,8 +132,9 @@ void perf_trace_destroy(struct perf_event *p_event)
 	struct ftrace_event_call *tp_event = p_event->tp_event;
 	int i;
 
+	mutex_lock(&event_mutex);
 	if (--tp_event->perf_refcount > 0)
-		return;
+		goto out;
 
 	if (tp_event->class->reg)
 		tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER);
@@ -142,6 +143,12 @@ void perf_trace_destroy(struct perf_event *p_event)
 					    tp_event->class->perf_probe,
 					    tp_event);
 
+	/*
+	 * Ensure our callback won't be called anymore. See
+	 * tracepoint_probe_unregister() and __DO_TRACE().
+	 */
+	synchronize_sched();
+
 	free_percpu(tp_event->perf_events);
 	tp_event->perf_events = NULL;
 
@@ -151,6 +158,8 @@ void perf_trace_destroy(struct perf_event *p_event)
 			perf_trace_buf[i] = NULL;
 		}
 	}
+out:
+	mutex_unlock(&event_mutex);
 }
 
 __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
@@ -169,7 +178,7 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
 	if (*rctxp < 0)
 		return NULL;
 
-	raw_data = per_cpu_ptr(perf_trace_buf[*rctxp], smp_processor_id());
+	raw_data = this_cpu_ptr(perf_trace_buf[*rctxp]);
 
 	/* zero the dead bytes from align to not leak stack to user */
 	memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index faf7cef..f52b5f5 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1359,7 +1359,7 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
 	for (i = 0; i < tp->nr_args; i++)
 		call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
 
-	head = per_cpu_ptr(call->perf_events, smp_processor_id());
+	head = this_cpu_ptr(call->perf_events);
 	perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
 }
 
@@ -1392,7 +1392,7 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
 	for (i = 0; i < tp->nr_args; i++)
 		call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
 
-	head = per_cpu_ptr(call->perf_events, smp_processor_id());
+	head = this_cpu_ptr(call->perf_events);
 	perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
 }
 
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index d2c859c..34e3580 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -519,7 +519,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 	syscall_get_arguments(current, regs, 0, sys_data->nb_args,
 			       (unsigned long *)&rec->args);
 
-	head = per_cpu_ptr(sys_data->enter_event->perf_events, smp_processor_id());
+	head = this_cpu_ptr(sys_data->enter_event->perf_events);
 	perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
 }
 
@@ -595,7 +595,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 	rec->nr = syscall_nr;
 	rec->ret = syscall_get_return_value(current, regs);
 
-	head = per_cpu_ptr(sys_data->exit_event->perf_events, smp_processor_id());
+	head = this_cpu_ptr(sys_data->exit_event->perf_events);
 	perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
 }