Merge tag 'trace-v4.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Various bug fixes:

   - Two small memory leaks in error paths.

   - A missed return error code on an error path.

   - A fix to check the tracing ring buffer CPU when it doesn't exist
     (caused by setting maxcpus on the command line that is less than
     the actual number of CPUs, and then onlining them manually).

   - A fix to have the reset of boot tracers called by lateinit_sync()
     instead of just lateinit(). As some of the tracers register via
     lateinit(), and if the clear happens before the tracer is
     registered, it will never start even though it was told to via the
     kernel command line"

* tag 'trace-v4.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix freeing of filter in create_filter() when set_str is false
  tracing: Fix kmemleak in tracing_map_array_free()
  ftrace: Check for null ret_stack on profile function graph entry function
  ring-buffer: Have ring_buffer_alloc_read_page() return error on offline CPU
  tracing: Missing error code in tracer_alloc_buffers()
  tracing: Call clear_boot_tracer() at lateinit_sync

1 files changed, 9 insertions, 5 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 529cc50d7243..81279c6602ff 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -4386,15 +4386,19 @@ EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
  * the page that was allocated, with the read page of the buffer.
  *
  * Returns:
- *  The page allocated, or NULL on error.
+ *  The page allocated, or ERR_PTR
  */
 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu)
 {
-	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+	struct ring_buffer_per_cpu *cpu_buffer;
 	struct buffer_data_page *bpage = NULL;
 	unsigned long flags;
 	struct page *page;
 
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return ERR_PTR(-ENODEV);
+
+	cpu_buffer = buffer->buffers[cpu];
 	local_irq_save(flags);
 	arch_spin_lock(&cpu_buffer->lock);
 
@@ -4412,7 +4416,7 @@ void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu)
 	page = alloc_pages_node(cpu_to_node(cpu),
 				GFP_KERNEL | __GFP_NORETRY, 0);
 	if (!page)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	bpage = page_address(page);
 
@@ -4467,8 +4471,8 @@ EXPORT_SYMBOL_GPL(ring_buffer_free_read_page);
  *
  * for example:
  *	rpage = ring_buffer_alloc_read_page(buffer, cpu);
- *	if (!rpage)
- *		return error;
+ *	if (IS_ERR(rpage))
+ *		return PTR_ERR(rpage);
  *	ret = ring_buffer_read_page(buffer, &rpage, len, cpu, 0);
  *	if (ret >= 0)
  *		process_page(rpage, ret);