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From:   Kuan-Wei Chiu <visitorckw@gmail.com>
To:     rafael@kernel.org
Cc:     daniel.lezcano@linaro.org, amitk@kernel.org, rui.zhang@intel.com,
        linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kuan-Wei Chiu <visitorckw@gmail.com>
Subject: [PATCH] tools/thermal: fix memory leak in realloc failure handling
Date:   Sun, 24 Sep 2023 14:50:13 +0800
Message-Id: <20230924065013.1081471-1-visitorckw@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In the previous code, there was a memory leak issue where the
previously allocated memory was not freed upon a failed realloc
operation. This patch addresses the problem by releasing the old memory
before setting the pointer to NULL in case of a realloc failure. This
ensures that memory is properly managed and avoids potential memory
leaks.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
---
 tools/thermal/lib/mainloop.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/thermal/lib/mainloop.c b/tools/thermal/lib/mainloop.c
index 94cbbcbd1c14..6dcc4090d47e 100644
--- a/tools/thermal/lib/mainloop.c
+++ b/tools/thermal/lib/mainloop.c
@@ -62,9 +62,13 @@ int mainloop_add(int fd, mainloop_callback_t cb, void *data)
 	struct mainloop_data *md;
 
 	if (fd >= nrhandler) {
-		mds = realloc(mds, sizeof(*mds) * (fd + 1));
-		if (!mds)
+		struct mainloop_data **mds_tmp =
+			realloc(mds, sizeof(*mds) * (fd + 1));
+		if (!mds_tmp) {
+			free(mds);
 			return -1;
+		}
+		mds = mds_tmp;
 		nrhandler = fd + 1;
 	}
 
-- 
2.25.1