[PATCH 4/5] hwmon: (pmbus/adm1266) include PEC byte in pmbus_block_xfer read buffer

[Abdurrahman Hussain]

adm1266_pmbus_block_xfer() sets up the read transaction with

	.buf = data->read_buf,
	.len = ADM1266_PMBUS_BLOCK_MAX + 2,

but read_buf in struct adm1266_data is declared as

	u8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 1];

For a max-length block response (length byte = 255 + up to 1 PEC
byte), the i2c controller is told to write 257 bytes into a 256-byte
buffer, putting one byte past the end of read_buf.  The same response
also makes the subsequent PEC compare

	if (crc != msgs[1].buf[msgs[1].buf[0] + 1])

read a byte beyond the array.

Bump the read_buf declaration to ADM1266_PMBUS_BLOCK_MAX + 2 so the
buffer can hold the length byte, up to 255 payload bytes, and the PEC
byte the i2c_msg length already accounts for.

Fixes: 407dc802a9c0 ("hwmon: (pmbus/adm1266) Add Block process call")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Abdurrahman Hussain <abdurrahman@xxxxxxxxxx>
---
 drivers/hwmon/pmbus/adm1266.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c
index 43d9e7407795..5c68e3177f64 100644
--- a/drivers/hwmon/pmbus/adm1266.c
+++ b/drivers/hwmon/pmbus/adm1266.c
@@ -61,7 +61,7 @@ struct adm1266_data {
 	u8 *dev_mem;
 	struct mutex buf_mutex;
 	u8 write_buf[ADM1266_PMBUS_BLOCK_MAX + 1] ____cacheline_aligned;
-	u8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 1] ____cacheline_aligned;
+	u8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 2] ____cacheline_aligned;
 };
 
 static const struct nvmem_cell_info adm1266_nvmem_cells[] = {

-- 
2.53.0