This is a note to let you know that I've just added the patch titled
i2c: i801: fix potential race in i801_block_transaction_byte_by_byte
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i2c-i801-fix-potential-race-in-i801_block_transaction_byte_by_byte.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f78ca48a8ba9cdec96e8839351e49eec3233b177 Mon Sep 17 00:00:00 2001
From: Heiner Kallweit <hkallweit1@xxxxxxxxx>
Date: Sat, 9 Sep 2023 22:25:06 +0200
Subject: i2c: i801: fix potential race in i801_block_transaction_byte_by_byte
From: Heiner Kallweit <hkallweit1@xxxxxxxxx>
commit f78ca48a8ba9cdec96e8839351e49eec3233b177 upstream.
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@xxxxxxxx>
Closes: https://lore.kernel.org/linux-i2c/20230828152747.09444625@endymion.delvare/
Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Andi Shyti <andi.shyti@xxxxxxxxxx>
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
Reviewed-by: Jean Delvare <jdelvare@xxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-i801.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -723,15 +723,11 @@ static int i801_block_transaction_byte_b
return i801_check_post(priv, status);
}
- for (i = 1; i <= len; i++) {
- if (i == len && read_write == I2C_SMBUS_READ)
- smbcmd |= SMBHSTCNT_LAST_BYTE;
- outb_p(smbcmd, SMBHSTCNT(priv));
-
- if (i == 1)
- outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START,
- SMBHSTCNT(priv));
+ if (len == 1 && read_write == I2C_SMBUS_READ)
+ smbcmd |= SMBHSTCNT_LAST_BYTE;
+ outb_p(smbcmd | SMBHSTCNT_START, SMBHSTCNT(priv));
+ for (i = 1; i <= len; i++) {
status = i801_wait_byte_done(priv);
if (status)
goto exit;
@@ -754,9 +750,12 @@ static int i801_block_transaction_byte_b
data->block[0] = len;
}
- /* Retrieve/store value in SMBBLKDAT */
- if (read_write == I2C_SMBUS_READ)
+ if (read_write == I2C_SMBUS_READ) {
data->block[i] = inb_p(SMBBLKDAT(priv));
+ if (i == len - 1)
+ outb_p(smbcmd | SMBHSTCNT_LAST_BYTE, SMBHSTCNT(priv));
+ }
+
if (read_write == I2C_SMBUS_WRITE && i+1 <= len)
outb_p(data->block[i+1], SMBBLKDAT(priv));
Patches currently in stable-queue which might be from hkallweit1@xxxxxxxxx are
queue-5.4/i2c-i801-fix-potential-race-in-i801_block_transaction_byte_by_byte.patch
