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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Jay Fang <f.fangjian@huawei.com>, Mark Brown <broonie@kernel.org>,
        Sasha Levin <sashal@kernel.org>, linux-spi@vger.kernel.org
Subject: [PATCH AUTOSEL 5.13 17/85] spi: spi-topcliff-pch: Fix potential double free in pch_spi_process_messages()
Date:   Sun,  4 Jul 2021 19:03:12 -0400
Message-Id: <20210704230420.1488358-17-sashal@kernel.org>
In-Reply-To: <20210704230420.1488358-1-sashal@kernel.org>
References: <20210704230420.1488358-1-sashal@kernel.org>
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From: Jay Fang <f.fangjian@huawei.com>

[ Upstream commit 026a1dc1af52742c5897e64a3431445371a71871 ]

pch_spi_set_tx() frees data->pkt_tx_buff on failure of kzalloc() for
data->pkt_rx_buff, but its caller, pch_spi_process_messages(), will
free data->pkt_tx_buff again. Set data->pkt_tx_buff to NULL after
kfree() to avoid double free.

Signed-off-by: Jay Fang <f.fangjian@huawei.com>
Link: https://lore.kernel.org/r/1620284888-65215-1-git-send-email-f.fangjian@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-topcliff-pch.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-topcliff-pch.c b/drivers/spi/spi-topcliff-pch.c
index b8870784fc6e..8c4615b76339 100644
--- a/drivers/spi/spi-topcliff-pch.c
+++ b/drivers/spi/spi-topcliff-pch.c
@@ -580,8 +580,10 @@ static void pch_spi_set_tx(struct pch_spi_data *data, int *bpw)
 	data->pkt_tx_buff = kzalloc(size, GFP_KERNEL);
 	if (data->pkt_tx_buff != NULL) {
 		data->pkt_rx_buff = kzalloc(size, GFP_KERNEL);
-		if (!data->pkt_rx_buff)
+		if (!data->pkt_rx_buff) {
 			kfree(data->pkt_tx_buff);
+			data->pkt_tx_buff = NULL;
+		}
 	}
 
 	if (!data->pkt_rx_buff) {
-- 
2.30.2