When clearing registers on new write requests was added, the protection
for currently running commands was missed leading to concurrent access
to the testunit registers. Check the flag beforehand.

Fixes: b39ab96aa894 ("i2c: testunit: add support for block process calls")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/i2c-slave-testunit.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/i2c-slave-testunit.c b/drivers/i2c/i2c-slave-testunit.c
index a5dcbc3c2c14..ca43e98cae1b 100644
--- a/drivers/i2c/i2c-slave-testunit.c
+++ b/drivers/i2c/i2c-slave-testunit.c
@@ -121,6 +121,9 @@ static int i2c_slave_testunit_slave_cb(struct i2c_client *client,
 		break;
 
 	case I2C_SLAVE_WRITE_REQUESTED:
+		if (test_bit(TU_FLAG_IN_PROCESS, &tu->flags))
+			return -EBUSY;
+
 		memset(tu->regs, 0, TU_NUM_REGS);
 		tu->reg_idx = 0;
 		break;
-- 
2.43.0

On Thu, Jun 27, 2024 at 01:14:48PM +0200, Wolfram Sang wrote:
> When clearing registers on new write requests was added, the protection
> for currently running commands was missed leading to concurrent access
> to the testunit registers. Check the flag beforehand.
> 
> Fixes: b39ab96aa894 ("i2c: testunit: add support for block process calls")
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Applied to for-current, thanks!

Hi Wolfram,

On Thu, Jun 27, 2024 at 01:14:48PM GMT, Wolfram Sang wrote:
> When clearing registers on new write requests was added, the protection
> for currently running commands was missed leading to concurrent access
> to the testunit registers. Check the flag beforehand.
> 
> Fixes: b39ab96aa894 ("i2c: testunit: add support for block process calls")
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

Thanks,
Andi