6 files changed, 20 insertions, 6 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 3c3ed639923d..b0963ac6fd16 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -5805,8 +5805,11 @@ __rb_get_reader_page_from_remote(struct ring_buffer_per_cpu *cpu_buffer)
 
 	prev_reader = cpu_buffer->subbuf_ids[cpu_buffer->meta_page->reader.id];
 
-	WARN_ON_ONCE(cpu_buffer->remote->swap_reader_page(cpu_buffer->cpu,
-							  cpu_buffer->remote->priv));
+	if (cpu_buffer->remote->swap_reader_page(cpu_buffer->cpu,
+						 cpu_buffer->remote->priv)) {
+		pr_warn_ratelimited("Remote reader page swap failed\n");
+		return NULL;
+	}
 	/* nr_pages doesn't include the reader page */
 	if (WARN_ON_ONCE(cpu_buffer->meta_page->reader.id > cpu_buffer->nr_pages))
 		return NULL;
diff --git a/kernel/trace/simple_ring_buffer.c b/kernel/trace/simple_ring_buffer.c
index f4642f5adda3..49913bb0057a 100644
--- a/kernel/trace/simple_ring_buffer.c
+++ b/kernel/trace/simple_ring_buffer.c
@@ -160,8 +160,8 @@ int simple_ring_buffer_swap_reader_page(struct simple_rb_per_cpu *cpu_buffer)
 		overrun = cpu_buffer->meta->overrun;
 	} while (!simple_bpage_unset_head_link(last, reader, SIMPLE_RB_LINK_NORMAL) && retry--);
 
-	if (!retry)
-		return -EINVAL;
+	if (retry < 0)
+		return -EBUSY;
 
 	cpu_buffer->head_page = simple_bpage_from_link(reader->link.next);
 	cpu_buffer->head_page->link.prev = &reader->link;
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3e0907aef172..a946e0183fd1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8216,6 +8216,8 @@ buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
 	/* Do not allow tracing while changing the order of the ring buffer */
 	tracing_stop_tr(tr);
 
+	trace_access_lock(RING_BUFFER_ALL_CPUS);
+
 	old_order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
 	if (old_order == order)
 		goto out;
@@ -8255,6 +8257,7 @@ buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
 #endif
 	(*ppos)++;
  out:
+	trace_access_unlock(RING_BUFFER_ALL_CPUS);
 	if (ret)
 		cnt = ret;
 	tracing_start_tr(tr);
@@ -9728,7 +9731,8 @@ __init static void enable_instances(void)
 
 		tr = trace_array_create_systems(name, NULL, addr, size);
 		if (IS_ERR(tr)) {
-			pr_warn("Tracing: Failed to create instance buffer %s\n", curr_str);
+			pr_warn("Tracing: Failed to create instance buffer '%s' (%ld)\n", name,
+				PTR_ERR(tr));
 			continue;
 		}
 
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 9f8f2d02276c..1d39eaf6a0f7 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -5019,6 +5019,8 @@ static __init void event_test_stuff(void)
 	struct task_struct *test_thread;
 
 	test_thread = kthread_run(event_test_thread, NULL, "test-events");
+	if (WARN_ON(IS_ERR(test_thread)))
+		return;
 	msleep(1);
 	kthread_stop(test_thread);
 }
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 893bd8b0e48a..963e0d6b61fd 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -6661,8 +6661,10 @@ static int hist_register_trigger(char *glob,
 		tracing_set_filter_buffering(file->tr, true);
 	}
 
-	if (named_data)
+	if (named_data) {
+		remove_hist_vars(hist_data);
 		destroy_hist_data(hist_data);
+	}
  out:
 	return ret;
 }
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index 2bbc89d4a266..93cda2f6f269 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -868,6 +868,9 @@ void user_event_mm_dup(struct task_struct *t, struct user_event_mm *old_mm)
 	struct user_event_mm *mm = user_event_mm_alloc(t);
 	struct user_event_enabler *enabler;
 
+	/* On failure, do not free parent's copy */
+	t->user_event_mm = NULL;
+
 	if (!mm)
 		return;