X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=lttng-events.c;h=bd6f44d977dba95e36c769f828b60e4fb9502c1f;hb=dcb93448766003b5d8d19a57e2dd44efa8ea0035;hp=1f34fbbc3341afd6ce8094c02fba4ed4b818bb70;hpb=43803cf2bdfe205fe0e426f7e93507d722ba1feb;p=lttng-modules.git

diff --git a/lttng-events.c b/lttng-events.c
index 1f34fbbc..bd6f44d9 100644
--- a/lttng-events.c
+++ b/lttng-events.c
@@ -1085,17 +1085,22 @@ int lttng_session_list_tracker_pids(struct lttng_session *session)
 		ret = PTR_ERR(tracker_pids_list_file);
 		goto file_error;
 	}
+	if (atomic_long_add_unless(&session->file->f_count,
+		1, INT_MAX) == INT_MAX) {
+		goto refcount_error;
+	}
 	ret = lttng_tracker_pids_list_fops.open(NULL, tracker_pids_list_file);
 	if (ret < 0)
 		goto open_error;
 	m = tracker_pids_list_file->private_data;
 	m->private = session;
 	fd_install(file_fd, tracker_pids_list_file);
-	atomic_long_inc(&session->file->f_count);
 
 	return file_fd;
 
 open_error:
+	atomic_long_dec(&session->file->f_count);
+refcount_error:
 	fput(tracker_pids_list_file);
 file_error:
 	put_unused_fd(file_fd);
@@ -2018,12 +2023,15 @@ int _lttng_event_header_declare(struct lttng_session *session)
  * taken at start of trace.
  * Yes, this is only an approximation. Yes, we can (and will) do better
  * in future versions.
+ * Return 0 if offset is negative. It may happen if the system sets
+ * the REALTIME clock to 0 after boot.
  */
 static
 uint64_t measure_clock_offset(void)
 {
-	uint64_t offset, monotonic[2], realtime;
+	uint64_t monotonic_avg, monotonic[2], realtime;
 	uint64_t tcf = trace_clock_freq();
+	int64_t offset;
 	struct timespec rts = { 0, 0 };
 	unsigned long flags;
 
@@ -2034,7 +2042,7 @@ uint64_t measure_clock_offset(void)
 	monotonic[1] = trace_clock_read64();
 	local_irq_restore(flags);
 
-	offset = (monotonic[0] + monotonic[1]) >> 1;
+	monotonic_avg = (monotonic[0] + monotonic[1]) >> 1;
 	realtime = (uint64_t) rts.tv_sec * tcf;
 	if (tcf == NSEC_PER_SEC) {
 		realtime += rts.tv_nsec;
@@ -2044,7 +2052,9 @@ uint64_t measure_clock_offset(void)
 		do_div(n, NSEC_PER_SEC);
 		realtime += n;
 	}
-	offset = realtime - offset;
+	offset = (int64_t) realtime - monotonic_avg;
+	if (offset < 0)
+		return 0;
 	return offset;
 }