i2c: imx: preserve error state in block data length handler

When a block read returns an invalid length, zero or >I2C_SMBUS_BLOCK_MAX,
the length handler sets the state to IMX_I2C_STATE_FAILED. However,
i2c_imx_master_isr() unconditionally overwrites this with
IMX_I2C_STATE_READ_CONTINUE, causing an endless read loop that overruns
buffers and crashes the system.

Guard the state transition to preserve error states set by the length
handler.

Fixes: 5f5c2d4579ca ("i2c: imx: prevent rescheduling in non dma mode")
Signed-off-by: LI Qingwu <[e-mail]>
Cc: <[e-mail]> # v6.13+
Reviewed-by: Stefan Eichenberger <[e-mail]>
Signed-off-by: Andi Shyti <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Wolfram Sang <[e-mail]>

drivers/i2c/busses/i2c-imx.c

···
 
 	case IMX_I2C_STATE_READ_BLOCK_DATA_LEN:
 		i2c_imx_isr_read_block_data_len(i2c_imx);
-		i2c_imx->state = IMX_I2C_STATE_READ_CONTINUE;
+		if (i2c_imx->state == IMX_I2C_STATE_READ_BLOCK_DATA_LEN)
+			i2c_imx->state = IMX_I2C_STATE_READ_CONTINUE;
 		break;
 
 	case IMX_I2C_STATE_WRITE: