Fix: sessiond: snapshot errors don't clear session's trace chunk

The snapshot record command is implemented by creating and setting
a new trace chunk on the target session, capturing the snapshot, and
closing the session's trace chunk once it is complete.

On some error paths, the session's newly created trace chunk is not
cleared. This means that the session is seen to have a
'current_trace_chunk' on the next attempt to record a snapshot; an
unexpected condition for which an assert() exists.

This results in the following crash:
lttng-sessiond: /home/smarchi/src/lttng-tools/src/bin/lttng-sessiond/cmd.c:4685: snapshot_record: Assertion `!session->current_trace_chunk' failed.

Ensure that the session's current trace chunk is closed and cleared
when an error occurs during the command's execution.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I4f78e3c324bee873349ed5b4d8e189a000458a07

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 1c53cadf824e7a5d7ab6f24cd43707a0af303f0d..93df59ccdc97d8fe26578866a96ff48229015110 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -4653,7 +4653,7 @@ enum lttng_error_code snapshot_record(struct ltt_session *session,
                        snapshot_output->max_size);
        if (nb_packets_per_stream < 0) {
                ret_code = LTTNG_ERR_MAX_SIZE_INVALID;
-               goto error;
+               goto error_close_trace_chunk;
        }
 
        if (session->kernel_session) {
@@ -4661,7 +4661,7 @@ enum lttng_error_code snapshot_record(struct ltt_session *session,
                                snapshot_kernel_consumer_output, session,
                                wait, nb_packets_per_stream);
                if (ret_code != LTTNG_OK) {
-                       goto error;
+                       goto error_close_trace_chunk;
                }
        }
 
@@ -4670,10 +4670,10 @@ enum lttng_error_code snapshot_record(struct ltt_session *session,
                                snapshot_ust_consumer_output, session,
                                wait, nb_packets_per_stream);
                if (ret_code != LTTNG_OK) {
-                       goto error;
+                       goto error_close_trace_chunk;
                }
        }
-
+error_close_trace_chunk:
        if (session_close_trace_chunk(
                            session, session->current_trace_chunk, NULL, NULL)) {
                /*