Fix: lttng: add-trigger: null dereference on MI initialization error

Failures to create an MI writer instance will result in a dereference of
the MI writer when attempting to close the command's output element.

1457842 Dereference after null check

Either the check against null is unnecessary, or there may be a null
pointer dereference.

In cmd_add_trigger: Pointer is checked against null but then
dereferenced anyway (CWE-476)

Reported-by: Coverity Scan
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I98b844d2f1c7abd43bd42ee472759de57b34484e

diff --git a/src/bin/lttng/commands/add_trigger.c b/src/bin/lttng/commands/add_trigger.c
index e4111eba095a494987f60740a1e191b921fd3973..00f8f47e363401400db7d613939b8be17923245e 100644 (file)
--- a/src/bin/lttng/commands/add_trigger.c
+++ b/src/bin/lttng/commands/add_trigger.c
@@ -2428,7 +2428,7 @@ error:
 
 end:
        /* Mi closing. */
-       if (lttng_opt_mi) {
+       if (lttng_opt_mi && mi_writer) {
                int mi_ret;
 
                /* Close output element. */