1 files changed, 18 insertions, 6 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index acbb0e73d3a2..1275175b0946 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3440,11 +3440,23 @@ EXPORT_SYMBOL_GPL(ring_buffer_iter_reset);
 int ring_buffer_iter_empty(struct ring_buffer_iter *iter)
 {
         struct ring_buffer_per_cpu *cpu_buffer;
+        struct buffer_page *reader;
+        struct buffer_page *head_page;
+        struct buffer_page *commit_page;
+        unsigned commit;
 
         cpu_buffer = iter->cpu_buffer;
 
-        return iter->head_page == cpu_buffer->commit_page &&
-                iter->head == rb_commit_index(cpu_buffer);
+        /* Remember, trace recording is off when iterator is in use */
+        reader = cpu_buffer->reader_page;
+        head_page = cpu_buffer->head_page;
+        commit_page = cpu_buffer->commit_page;
+        commit = rb_page_commit(commit_page);
+
+        return ((iter->head_page == commit_page && iter->head == commit) ||
+                (iter->head_page == reader && commit_page == head_page &&
+                 head_page->read == commit &&
+                 iter->head == rb_page_commit(cpu_buffer->reader_page)));
 }
 EXPORT_SYMBOL_GPL(ring_buffer_iter_empty);
 
@@ -4875,9 +4887,9 @@ static __init int test_ringbuffer(void)
                 rb_data[cpu].cnt = cpu;
                 rb_threads[cpu] = kthread_create(rb_test, &rb_data[cpu],
                                                  "rbtester/%d", cpu);
-                if (WARN_ON(!rb_threads[cpu])) {
+                if (WARN_ON(IS_ERR(rb_threads[cpu]))) {
                         pr_cont("FAILED\n");
-                        ret = -1;
+                        ret = PTR_ERR(rb_threads[cpu]);
                         goto out_free;
                 }
 
@@ -4887,9 +4899,9 @@ static __init int test_ringbuffer(void)
 
         /* Now create the rb hammer! */
         rb_hammer = kthread_run(rb_hammer_test, NULL, "rbhammer");
-        if (WARN_ON(!rb_hammer)) {
+        if (WARN_ON(IS_ERR(rb_hammer))) {
                 pr_cont("FAILED\n");
-                ret = -1;
+                ret = PTR_ERR(rb_hammer);
                 goto out_free;
         }