[PATCH v2] tracing: Replace strncpy() with strscpy() when copying comm

[Jinjie Ruan <ruanjinjie@huawei.com>]

Replace the depreciated[1] strncpy() calls with strscpy()
when copying comm.

Link: https://github.com/KSPP/linux/issues/90 [1]
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
v2:
- Fix the trace_events_hist.c build problem.
---
 kernel/trace/trace.c              | 2 +-
 kernel/trace/trace_events_hist.c  | 4 ++--
 kernel/trace/trace_sched_switch.c | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a8f52b6527ca..cb2c66554212 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1934,7 +1934,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 	max_data->critical_start = data->critical_start;
 	max_data->critical_end = data->critical_end;
 
-	strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
+	strscpy(max_data->comm, tsk->comm);
 	max_data->pid = tsk->pid;
 	/*
 	 * If tsk == current, then use current_uid(), as that does not use
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 5f9119eb7c67..8e370bc4faa4 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1599,7 +1599,7 @@ static inline void save_comm(char *comm, struct task_struct *task)
 		return;
 	}
 
-	strncpy(comm, task->comm, TASK_COMM_LEN);
+	strscpy(comm, task->comm, TASK_COMM_LEN);
 }
 
 static void hist_elt_data_free(struct hist_elt_data *elt_data)
@@ -3405,7 +3405,7 @@ static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
 	elt_data = context->elt->private_data;
 	track_elt_data = track_data->elt.private_data;
 	if (elt_data->comm)
-		strncpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
+		strscpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
 
 	track_data->updated = true;
 
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 8a407adb0e1c..573b5d8e8a28 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -187,7 +187,7 @@ static inline char *get_saved_cmdlines(int idx)
 
 static inline void set_cmdline(int idx, const char *cmdline)
 {
-	strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
+	strscpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
 }
 
 static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
-- 
2.34.1