Fix: use a free running channel key between sessiond and kernel consumer

[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 2cbed381870a096350a4e8ac77ec39845850d0f1..535a5b8e8c4035918f0e2665ac0af8f0e7ad8eda 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -34,6 +34,12 @@
 #include "kern-modules.h"
 #include "utils.h"
 
+/*
+ * Key used to reference a channel between the sessiond and the consumer. This
+ * is only read and updated with the session_list lock held.
+ */
+static uint64_t next_kernel_channel_key;
+
 /*
  * Add context on a kernel channel.
  *
@@ -169,8 +175,10 @@ int kernel_create_channel(struct ltt_kernel_session *session,
        cds_list_add(&lkc->list, &session->channel_list.head);
        session->channel_count++;
        lkc->session = session;
+       lkc->key = ++next_kernel_channel_key;
 
-       DBG("Kernel channel %s created (fd: %d)", lkc->channel->name, lkc->fd);
+       DBG("Kernel channel %s created (fd: %d, key: %" PRIu64 ")",
+                       lkc->channel->name, lkc->fd, lkc->key);
 
        return 0;
 
@@ -291,7 +299,8 @@ int kernel_disable_channel(struct ltt_kernel_channel *chan)
        }
 
        chan->enabled = 0;
-       DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd);
+       DBG("Kernel channel %s disabled (fd: %d, key: %" PRIu64 ")",
+                       chan->channel->name, chan->fd, chan->key);
 
        return 0;
 
@@ -315,7 +324,8 @@ int kernel_enable_channel(struct ltt_kernel_channel *chan)
        }
 
        chan->enabled = 1;
-       DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd);
+       DBG("Kernel channel %s enabled (fd: %d, key: %" PRIu64 ")",
+                       chan->channel->name, chan->fd, chan->key);
 
        return 0;
 
@@ -1029,12 +1039,10 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess,
 
                /* For each channel, ask the consumer to snapshot it. */
                cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
-                       pthread_mutex_lock(socket->lock);
                        ret = consumer_snapshot_channel(socket, chan->fd, output, 0,
                                        ksess->uid, ksess->gid,
                                        DEFAULT_KERNEL_TRACE_DIR, wait,
                                        nb_packets_per_stream);
-                       pthread_mutex_unlock(socket->lock);
                        if (ret < 0) {
                                ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
                                (void) kernel_consumer_destroy_metadata(socket,
@@ -1044,11 +1052,9 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess,
                }
 
                /* Snapshot metadata, */
-               pthread_mutex_lock(socket->lock);
                ret = consumer_snapshot_channel(socket, ksess->metadata->fd, output,
                                1, ksess->uid, ksess->gid,
                                DEFAULT_KERNEL_TRACE_DIR, wait, 0);
-               pthread_mutex_unlock(socket->lock);
                if (ret < 0) {
                        ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
                        goto error_consumer;