[PATCH] tracing: fprobe: fix the length of unused fgraph_data

[Martin Kaiser]

If fprobe_entry does not fill the allocated fgraph_data completely, the
unused part is zeroed with memset.

Fix the length for this memset call. Both reserved_words and used are in
units of return stack words, but memset needs the number of bytes.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer")
Signed-off-by: Martin Kaiser <martin@xxxxxxxxx>
---
 kernel/trace/fprobe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index dcadf1d23b8a..6a1192515afd 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -451,7 +451,7 @@ static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops
 		}
 	}
 	if (used < reserved_words)
-		memset(fgraph_data + used, 0, reserved_words - used);
+		memset(fgraph_data + used, 0, (reserved_words - used) * sizeof(long));
 
 	/* If any exit_handler is set, data must be used. */
 	return used != 0;
-- 
2.43.7