Merge tag 'trace-fixes-v3.16-rc5-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
"A few more fixes for ftrace infrastructure.

I was cleaning out my INBOX and found two fixes from zhangwei from a
year ago that were lost in my mail. These fix an inconsistency
between trace_puts() and the way trace_printk() works. The reason
this is important to fix is because when trace_printk() doesn't have
any arguments, it turns into a trace_puts(). Not being able to enable
a stack trace against trace_printk() because it does not have any
arguments is quite confusing. Also, the fix is rather trivial and low
risk.

While porting some changes to PowerPC I discovered that it still has
the function graph tracer filter bug that if you also enable stack
tracing the function graph tracer filter is ignored. I fixed that up.

Finally, Martin Lau, fixed a bug that would cause readers of the
ftrace ring buffer to block forever even though it was suppose to be
NONBLOCK"

This also includes the fix from an earlier pull request:

"Oleg Nesterov fixed a memory leak that happens if a user creates a
tracing instance, sets up a filter in an event, and then removes that
instance. The filter allocates memory that is never freed when the
instance is destroyed"

* tag 'trace-fixes-v3.16-rc5-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ring-buffer: Fix polling on trace_pipe
tracing: Add TRACE_ITER_PRINTK flag check in __trace_puts/__trace_bputs
tracing: Fix graph tracer with stack tracer on other archs
tracing: Add ftrace_trace_stack into __trace_puts/__trace_bputs
tracing: instance_rmdir() leaks ftrace_event_file->filter

kernel/trace/ftrace.c

···
 		func = ftrace_ops_list_func;
 	}
 
+	update_function_graph_func();
+
 	/* If there's no change, then do nothing more here */
 	if (ftrace_trace_function == func)
 		return;
-
-	update_function_graph_func();
 
 	/*
 	 * If we are using the list function, it doesn't care

kernel/trace/ring_buffer.c

···
 	struct ring_buffer_per_cpu *cpu_buffer;
 	struct rb_irq_work *work;
 
-	if ((cpu == RING_BUFFER_ALL_CPUS && !ring_buffer_empty(buffer)) ||
-	    (cpu != RING_BUFFER_ALL_CPUS && !ring_buffer_empty_cpu(buffer, cpu)))
-		return POLLIN | POLLRDNORM;
-
 	if (cpu == RING_BUFFER_ALL_CPUS)
 		work = &buffer->irq_work;
 	else {

kernel/trace/trace.c

···
 	struct print_entry *entry;
 	unsigned long irq_flags;
 	int alloc;
+	int pc;
+
+	if (!(trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	pc = preempt_count();
 
 	if (unlikely(tracing_selftest_running || tracing_disabled))
 		return 0;
···
 	local_save_flags(irq_flags);
 	buffer = global_trace.trace_buffer.buffer;
 	event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, 
-					  irq_flags, preempt_count());
+					  irq_flags, pc);
 	if (!event)
 		return 0;
 
···
 		entry->buf[size] = '\0';
 
 	__buffer_unlock_commit(buffer, event);
+	ftrace_trace_stack(buffer, irq_flags, 4, pc);
 
 	return size;
 }
···
 	struct bputs_entry *entry;
 	unsigned long irq_flags;
 	int size = sizeof(struct bputs_entry);
+	int pc;
+
+	if (!(trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	pc = preempt_count();
 
 	if (unlikely(tracing_selftest_running || tracing_disabled))
 		return 0;
···
 	local_save_flags(irq_flags);
 	buffer = global_trace.trace_buffer.buffer;
 	event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
-					  irq_flags, preempt_count());
+					  irq_flags, pc);
 	if (!event)
 		return 0;
 
···
 	entry->str			= str;
 
 	__buffer_unlock_commit(buffer, event);
+	ftrace_trace_stack(buffer, irq_flags, 4, pc);
 
 	return 1;
 }

kernel/trace/trace_events.c

···
 
 	list_del(&file->list);
 	remove_subsystem(file->system);
+	free_event_filter(file->filter);
 	kmem_cache_free(file_cachep, file);
 }