[PATCH 2/3] tracing: Adding additional NULL checks.

From: Divya Indi
Date: Wed Jun 12 2019 - 12:40:06 EST


commit f45d1225adb0 ("tracing: Kernel access to Ftrace instances")
exported certain functions providing access to Ftrace instances from
other kernel components.
Adding some additional NULL checks to ensure safe usage by the users.

Signed-off-by: Divya Indi <divya.indi@xxxxxxxxxx>
---
kernel/trace/trace.c | 3 +++
kernel/trace/trace_events.c | 2 ++
2 files changed, 5 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1c80521..a60dc13 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3205,6 +3205,9 @@ int trace_array_printk(struct trace_array *tr,
if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
return 0;

+ if (!tr)
+ return -EINVAL;
+
va_start(ap, fmt);
ret = trace_array_vprintk(tr, ip, fmt, ap);
va_end(ap);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index b6b4618..445b059 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -800,6 +800,8 @@ int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
char *event = NULL, *sub = NULL, *match;
int ret;

+ if (!tr)
+ return -ENODEV;
/*
* The buf format can be <subsystem>:<event-name>
* *:<event-name> means any event by that name.
--
1.8.3.1