[PATCH 6.6 098/160] iio: imu: bmi160: Remove potential undefined behavior in bmi160_config_pin()

Greg Kroah-Hartman
2026-04-08T18:24:53Z

From: Josh Poimboeuf <jpoimboe@kernel.org>

commit c05a87d9ec3bf8727a5d746ce855003c6f2f8bb4 upstream.

If 'pin' is not one of its expected values, the value of
'int_out_ctrl_shift' is undefined. With UBSAN enabled, this causes
Clang to generate undefined behavior, resulting in the following
warning:

drivers/iio/imu/bmi160/bmi160_core.o: warning: objtool: bmi160_setup_irq() falls through to next function __cfi_bmi160_core_runtime_resume()

Prevent the UB and improve error handling by returning an error if 'pin'
has an unexpected value.

While at it, simplify the code a bit by moving the 'pin_name' assignment
to the first switch statement.

Fixes: 895bf81e6bbf ("iio:bmi160: add drdy interrupt support")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.fastmail.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iio/imu/bmi160/bmi160_core.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

--- a/drivers/iio/imu/bmi160/bmi160_core.c
+++ b/drivers/iio/imu/bmi160/bmi160_core.c
@@ -568,12 +568,16 @@ static int bmi160_config_pin(struct regm
int_out_ctrl_shift = BMI160_INT1_OUT_CTRL_SHIFT;
int_latch_mask = BMI160_INT1_LATCH_MASK;
int_map_mask = BMI160_INT1_MAP_DRDY_EN;
+ pin_name = "INT1";
break;
case BMI160_PIN_INT2:
int_out_ctrl_shift = BMI160_INT2_OUT_CTRL_SHIFT;
int_latch_mask = BMI160_INT2_LATCH_MASK;
int_map_mask = BMI160_INT2_MAP_DRDY_EN;
+ pin_name = "INT2";
break;
+ default:
+ return -EINVAL;
}
int_out_ctrl_mask = BMI160_INT_OUT_CTRL_MASK << int_out_ctrl_shift;

@@ -607,17 +611,8 @@ static int bmi160_config_pin(struct regm
ret = bmi160_write_conf_reg(regmap, BMI160_REG_INT_MAP,
int_map_mask, int_map_mask,
write_usleep);
- if (ret) {
- switch (pin) {
- case BMI160_PIN_INT1:
- pin_name = "INT1";
- break;
- case BMI160_PIN_INT2:
- pin_name = "INT2";
- break;
- }
+ if (ret)
dev_err(dev, "Failed to configure %s IRQ pin", pin_name);
- }

return ret;
}