linux-kernel - [PATCH v2] tracing/eprobe: Replace snprintf with memcpy

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Message-Id: <20230109033213.3220884-1-quanfafu@gmail.com>
Date:   Mon,  9 Jan 2023 11:32:13 +0800
From:   Quanfa Fu <quanfafu@...il.com>
To:     rostedt@...dmis.org, mhiramat@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
        Quanfa Fu <quanfafu@...il.com>
Subject: [PATCH v2] tracing/eprobe: Replace snprintf with memcpy

No need to check for negative return value from snprintf() as the
code does not return negative values. Replace snprintf with memcpy.

Signed-off-by: Quanfa Fu <quanfafu@...il.com>

-----
V1 -> V2: memory allc uses kzalloc and replace snprintf with memcpy
---
 kernel/trace/trace_eprobe.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 352b65e2b910..56eb39f495f6 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -905,7 +905,7 @@ static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[
 static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[])
 {
 	struct event_filter *dummy = NULL;
-	int i, ret, len = 0;
+	int i, ret, arg_len, len = 0;
 	char *p;
 
 	if (argc == 0) {
@@ -923,17 +923,17 @@ static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const ch
 
 	p = ep->filter_str;
 	for (i = 0; i < argc; i++) {
-		ret = snprintf(p, len, "%s ", argv[i]);
-		if (ret < 0)
-			goto error;
-		if (ret > len) {
-			ret = -E2BIG;
-			goto error;
-		}
-		p += ret;
-		len -= ret;
+		arg_len = strlen(argv[i]);
+		memcpy((void *)p, argv[i], arg_len);
+
+		if (i == argc - 1)
+			p[arg_len] = '\0';
+		else
+			p[arg_len] = ' ';
+
+		p += arg_len + 1;
+		len -= arg_len + 1;
 	}
-	p[-1] = '\0';
 
 	/*
 	 * Ensure the filter string can be parsed correctly. Note, this
-- 
2.31.1