[PATCH] tracing: Replace strncpy with memcpy for fixed-length substring copy

From: Siddarth G
Date: Tue Mar 25 2025 - 14:13:07 EST


checkpatch.pl reports the following warning:
WARNING: Prefer strscpy, strscpy_pad, or __nonstring over strncpy
(see: https://github.com/KSPP/linux/issues/90)

In synth_field_string_size(), replace strncpy() with memcpy() to copy 'len'
characters from 'start' to 'buf'. The code manually adds a NUL terminator
after the copy, making memcpy safe here.

Signed-off-by: Siddarth G <siddarthsgml@xxxxxxxxx>
---
kernel/trace/trace_events_synth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index e3f7d09e5512..1aaa9a5e2aca 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -207,7 +207,7 @@ static int synth_field_string_size(char *type)
if (len == 0)
return 0; /* variable-length string */

- strncpy(buf, start, len);
+ memcpy(buf, start, len);
buf[len] = '\0';

err = kstrtouint(buf, 0, &size);
--
2.43.0