linux-kernel - [PATCH] input: atmel_mxt

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Date:   Mon,  3 Aug 2020 06:48:32 -0700
From:   trix@...hat.com
To:     nick@...anahar.org, dmitry.torokhov@...il.com,
        ezequiel@...labora.com, bleung@...omium.org
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        Tom Rix <trix@...hat.com>
Subject: [PATCH] input: atmel_mxt_ts: fix double free

From: Tom Rix <trix@...hat.com>

Clang static analysis reports this error

atmel_mxt_ts.c:1850:2: warning: Attempt to free released memory
        kfree(id_buf);
        ^~~~~~~~~~~~~

The problem is with this code block

data->raw_info_block = id_buf;
...
error = mxt_parse_object_table(data, id_buf + MXT_OBJECT_START);
if (error) {
	dev_err(&client->dev, "Error %d parsing object table\n", error);
	mxt_free_object_table(data);
	goto err_free_mem;
}

mxt_free_object_table() frees id_buf

kfree(data->raw_info_block);

So skip over the second free

Fixes: 068bdb67ef74 ("Input: atmel_mxt_ts - fix the firmware update")

Signed-off-by: Tom Rix <trix@...hat.com>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 6b71b0aff115..1cc0f492f4f4 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -1839,7 +1839,7 @@ static int mxt_read_info_block(struct mxt_data *data)
 	if (error) {
 		dev_err(&client->dev, "Error %d parsing object table\n", error);
 		mxt_free_object_table(data);
-		goto err_free_mem;
+		goto err_free_mem1;
 	}
 
 	data->object_table = (struct mxt_object *)(id_buf + MXT_OBJECT_START);
@@ -1848,6 +1848,7 @@ static int mxt_read_info_block(struct mxt_data *data)
 
 err_free_mem:
 	kfree(id_buf);
+err_free_mem1:
 	return error;
 }
 
-- 
2.18.1