[PATCH AUTOSEL 4.9 02/20] spi: spi-topcliff-pch: Fix potential double free in pch_spi_process_messages()

[Sasha Levin <sashal@xxxxxxxxxx>]

From: Jay Fang <f.fangjian@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Link: https://lore.kernel.org/r/1620284888-65215-1-git-send-email-f.fangjian@xxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 fe707440f8c3..9b24ebbba346 100644
--- a/drivers/spi/spi-topcliff-pch.c
+++ b/drivers/spi/spi-topcliff-pch.c
@@ -585,8 +585,10 @@ 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