From: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Date: Thu, 1 Sep 2016 21:52:09 +0000 (-0400)
Subject: Fix: unregister cpu hotplug notifier on buffer alloc error
X-Git-Tag: v2.9.0-rc1~20
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=769b62a02f62ff8db93f109d9f63a1df6ea9990b;p=lttng-modules.git

Fix: unregister cpu hotplug notifier on buffer alloc error

The cpu hotplug notifier needs to be unregistered in the error path of
buffer allocation, else it eventually causes kernel OOPS when the kernel
accesses freed memory of the notifier block.

Fixes #1031

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/lib/ringbuffer/ring_buffer_backend.c b/lib/ringbuffer/ring_buffer_backend.c
index 451ce23b..c7f2fe9d 100644
--- a/lib/ringbuffer/ring_buffer_backend.c
+++ b/lib/ringbuffer/ring_buffer_backend.c
@@ -422,6 +422,7 @@ free_bufs:
 		}
 #ifdef CONFIG_HOTPLUG_CPU
 		put_online_cpus();
+		unregister_hotcpu_notifier(&chanb->cpu_hp_notifier);
 #endif
 		free_percpu(chanb->buf);
 	} else