ring-buffer: Move resize integrity check under reader lock
While using an application that does splice on the ftrace ring
buffer at start up, I triggered an integrity check failure.
Looking into this, I discovered that resizing the buffer performs
an integrity check after the buffer is resized. This check unfortunately
is preformed after it releases the reader lock. If a reader is
reading the buffer it may cause the integrity check to trigger a
false failure.
This patch simply moves the integrity checker under the protection
of the ring buffer reader lock.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 0d64c51..eccb4cf 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1208,9 +1208,9 @@
return;
rb_reset_cpu(cpu_buffer);
- spin_unlock_irq(&cpu_buffer->reader_lock);
-
rb_check_pages(cpu_buffer);
+
+ spin_unlock_irq(&cpu_buffer->reader_lock);
}
static void
@@ -1233,9 +1233,9 @@
list_add_tail(&bpage->list, cpu_buffer->pages);
}
rb_reset_cpu(cpu_buffer);
- spin_unlock_irq(&cpu_buffer->reader_lock);
-
rb_check_pages(cpu_buffer);
+
+ spin_unlock_irq(&cpu_buffer->reader_lock);
}
/**