From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 13 Mar 2012 20:09:52 +0000 (-0400)
Subject: Ensure that multiplication of clock offset is done on 64-bit
X-Git-Tag: v2.0.0-rc3~4
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=17ec046afa9b641b95951ca9594c3b7351d5e658;p=lttng-ust.git

Ensure that multiplication of clock offset is done on 64-bit

This is not a bug in UST per se, because we happen to force
multiplication by a ULL number, but force cast to uint64_t anyway to
ensure we don't trigger this overflow if the constant ever happen to
change.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/liblttng-ust/ltt-events.c b/liblttng-ust/ltt-events.c
index d9bf555a..2b06f3c0 100644
--- a/liblttng-ust/ltt-events.c
+++ b/liblttng-ust/ltt-events.c
@@ -1088,7 +1088,7 @@ uint64_t measure_clock_offset(void)
 		return 0;
 	monotonic[1] = trace_clock_read64();
 	offset = (monotonic[0] + monotonic[1]) >> 1;
-	realtime = rts.tv_sec * 1000000000ULL;
+	realtime = (uint64_t) rts.tv_sec * 1000000000ULL;
 	realtime += rts.tv_nsec;
 	offset = realtime - offset;
 	return offset;