iolog: fix reported defect from coverity scan

Fix the two Null pointer dereferences issue reported by Coverity scan

Null pointer dereferences  (FORWARD_NULL)
Dereferencing null pointer "l->td"

Null pointer dereferences  (REVERSE_INULL)
Null-checking "p->td" suggests that it may be null, but it has already
been dereferenced on all paths leading to the check.

For aggregate read, write and trim bandwidth log, the setup_log function
gets called with NULL pointer reference for thread data. Thus before
dereferencing further we should check "l->td".

Signed-off-by: Ankit Kumar <ankit.kumar@samsung.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/iolog.c b/iolog.c
index b4c7a8f13..f52a9a80f 100644
--- a/iolog.c
+++ b/iolog.c
@@ -862,7 +862,12 @@ void setup_log(struct io_log **log, struct log_params *p,
 		l->log_ddir_mask = LOG_OFFSET_SAMPLE_BIT;
 	if (l->log_prio)
 		l->log_ddir_mask |= LOG_PRIO_SAMPLE_BIT;
-	if (l->td->o.log_max == IO_LOG_SAMPLE_BOTH)
+	/*
+	 * The bandwidth-log option generates agg-read_bw.log,
+	 * agg-write_bw.log and agg-trim_bw.log for which l->td is NULL.
+	 * Check if l->td is valid before dereferencing it.
+	 */
+	if (l->td && l->td->o.log_max == IO_LOG_SAMPLE_BOTH)
 		l->log_ddir_mask |= LOG_AVG_MAX_SAMPLE_BIT;
 
 	INIT_FLIST_HEAD(&l->chunk_list);