From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Thu, 29 Mar 2018 19:13:34 +0000 (-0400)
Subject: Fix: unhandled prev_seq initial value
X-Git-Tag: v2.11.0-rc1~316
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=3765c8cc40733ddde776d57c1ece30f2b05beea4;p=lttng-tools.git

Fix: unhandled prev_seq initial value

The previous sequence number of a stream is initialized to -1ULL
and comparing the current sequence number against it to perform
a rotation will yield unexepected results.

The assumption that the previous sequence number is less than
the current one is assert()'ed on elsewhere.

This case triggers whenever a rotation is performed before the
relay daemon has received a packet for a given stream.

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

diff --git a/src/bin/lttng-relayd/main.c b/src/bin/lttng-relayd/main.c
index f68ecdfbc..e3c070f8b 100644
--- a/src/bin/lttng-relayd/main.c
+++ b/src/bin/lttng-relayd/main.c
@@ -1722,7 +1722,8 @@ int try_rotate_stream(struct relay_stream *stream)
 		goto end;
 	}
 
-	if (stream->prev_seq < stream->rotate_at_seq_num) {
+	if (stream->prev_seq < stream->rotate_at_seq_num ||
+			stream->prev_seq == -1ULL) {
 		DBG("Stream %" PRIu64 " no yet ready for rotation",
 				stream->stream_handle);
 		goto end;