Fix: unregister cpu hotplug notifier on buffer alloc error

[lttng-modules.git] / lib / ringbuffer / ring_buffer_backend.c

diff --git a/lib/ringbuffer/ring_buffer_backend.c b/lib/ringbuffer/ring_buffer_backend.c
index f7ed20df19869b767fd23f568c87e5831956ead2..ad7611361b56aaad7805d8e579d5f1a2dc700df0 100644 (file)
--- a/lib/ringbuffer/ring_buffer_backend.c
+++ b/lib/ringbuffer/ring_buffer_backend.c
@@ -331,6 +331,12 @@ int channel_backend_init(struct channel_backend *chanb,
                return -EINVAL;
        if (!num_subbuf || (num_subbuf & (num_subbuf - 1)))
                return -EINVAL;
+       /*
+        * Overwrite mode buffers require at least 2 subbuffers per
+        * buffer.
+        */
+       if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2)
+               return -EINVAL;
 
        ret = subbuffer_id_check_index(config, num_subbuf);
        if (ret)
@@ -415,6 +421,7 @@ free_bufs:
                }
 #ifdef CONFIG_HOTPLUG_CPU
                put_online_cpus();
+               unregister_hotcpu_notifier(&chanb->cpu_hp_notifier);
 #endif
                free_percpu(chanb->buf);
        } else
@@ -686,8 +693,7 @@ void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bu
                                                        + (offset & ~PAGE_MASK),
                                                        src, pagecpy) != 0;
                if (ret > 0) {
-                       offset += (pagecpy - ret);
-                       len -= (pagecpy - ret);
+                       /* Copy failed. */
                        _lib_ring_buffer_memset(bufb, offset, 0, len, 0);
                        break; /* stop copy */
                }