i2c: i801: fix potential race in i801_block_transaction_byte_by_byte
authorHeiner Kallweit <hkallweit1@gmail.com>
Sat, 9 Sep 2023 20:25:06 +0000 (22:25 +0200)
committerWolfram Sang <wsa@kernel.org>
Tue, 19 Sep 2023 08:56:27 +0000 (10:56 +0200)
commitf78ca48a8ba9cdec96e8839351e49eec3233b177
treefa13578213a1621b69aa4eebff6748915a250a91
parentce9ecca0238b140b88f43859b211c9fdfd8e5b70
i2c: i801: fix potential race in i801_block_transaction_byte_by_byte

Currently we set SMBHSTCNT_LAST_BYTE only after the host has started
receiving the last byte. If we get e.g. preempted before setting
SMBHSTCNT_LAST_BYTE, the host may be finished with receiving the byte
before SMBHSTCNT_LAST_BYTE is set.
Therefore change the code to set SMBHSTCNT_LAST_BYTE before writing
SMBHSTSTS_BYTE_DONE for the byte before the last byte. Now the code
is also consistent with what we do in i801_isr_byte_done().

Reported-by: Jean Delvare <jdelvare@suse.com>
Closes: https://lore.kernel.org/linux-i2c/20230828152747.09444625@endymion.delvare/
Cc: stable@vger.kernel.org
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
drivers/i2c/busses/i2c-i801.c