linux-kernel - [PATCH AUTOSEL 5.4 3/3] recordmcount: Fix memory leaks in the uwrite function

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Message-Id: <20230509035616.60683-3-sashal@kernel.org>
Date:   Mon,  8 May 2023 23:56:11 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Hao Zeng <zenghao@...inos.cn>,
        Steven Rostedt <rostedt@...dmis.org>,
        Sasha Levin <sashal@...nel.org>, chenhuacai@...nel.org,
        zhangqing@...ngson.cn
Subject: [PATCH AUTOSEL 5.4 3/3] recordmcount: Fix memory leaks in the uwrite function

From: Hao Zeng <zenghao@...inos.cn>

[ Upstream commit fa359d068574d29e7d2f0fdd0ebe4c6a12b5cfb9 ]

Common realloc mistake: 'file_append' nulled but not freed upon failure

Link: https://lkml.kernel.org/r/20230426010527.703093-1-zenghao@kylinos.cn

Signed-off-by: Hao Zeng <zenghao@...inos.cn>
Suggested-by: Steven Rostedt <rostedt@...dmis.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 scripts/recordmcount.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index cce12e1971d85..ec692af8ce9eb 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -102,6 +102,7 @@ static ssize_t uwrite(void const *const buf, size_t const count)
 {
 	size_t cnt = count;
 	off_t idx = 0;
+	void *p = NULL;
 
 	file_updated = 1;
 
@@ -109,7 +110,10 @@ static ssize_t uwrite(void const *const buf, size_t const count)
 		off_t aoffset = (file_ptr + count) - file_end;
 
 		if (aoffset > file_append_size) {
-			file_append = realloc(file_append, aoffset);
+			p = realloc(file_append, aoffset);
+			if (!p)
+				free(file_append);
+			file_append = p;
 			file_append_size = aoffset;
 		}
 		if (!file_append) {
-- 
2.39.2