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);