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Tue, 10 Mar 2026 07:56:34 -0700 (PDT) Received: from [192.168.1.187] ([148.63.225.166]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48541aa7aacsm100218115e9.13.2026.03.10.07.56.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Mar 2026 07:56:34 -0700 (PDT) Message-ID: <26ee13c084488bb66aec8e240e416e3e43f3b697.camel@gmail.com> Subject: Re: [PATCH v2] iio: imu: bmi160: Remove potential undefined behavior in bmi160_config_pin() From: Nuno =?ISO-8859-1?Q?S=E1?= To: Josh Poimboeuf , linux-iio@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jonathan Cameron , David Lechner , Nuno =?ISO-8859-1?Q?S=E1?= , Andy Shevchenko , Peter Zijlstra , Nathan Chancellor , Arnd Bergmann Date: Tue, 10 Mar 2026 14:57:19 +0000 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2026-03-09 at 20:45 -0700, Josh Poimboeuf wrote: > If 'pin' is not one of its expected values, the value of > 'int_out_ctrl_shift' is undefined.=C2=A0 With UBSAN enabled, this causes > Clang to generate undefined behavior, resulting in the following > warning: >=20 > =C2=A0 drivers/iio/imu/bmi160/bmi160_core.o: warning: objtool: bmi160_set= up_irq() falls through to next > function __cfi_bmi160_core_runtime_resume() >=20 > Prevent the UB and improve error handling by returning an error if 'pin' > has an unexpected value. >=20 > While at it, simplify the code a bit by moving the 'pin_name' assignment > to the first switch statement. >=20 > Fixes: 895bf81e6bbf ("iio:bmi160: add drdy interrupt support") > Reported-by: Arnd Bergmann > Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.= fastmail.com > Signed-off-by: Josh Poimboeuf > --- Reviewed-by: Nuno S=C3=A1 > =C2=A0drivers/iio/imu/bmi160/bmi160_core.c | 15 +++++---------- > =C2=A01 file changed, 5 insertions(+), 10 deletions(-) >=20 > diff --git a/drivers/iio/imu/bmi160/bmi160_core.c b/drivers/iio/imu/bmi16= 0/bmi160_core.c > index 5f47708b4c5d..4abb83b75e2e 100644 > --- a/drivers/iio/imu/bmi160/bmi160_core.c > +++ b/drivers/iio/imu/bmi160/bmi160_core.c > @@ -573,12 +573,16 @@ static int bmi160_config_pin(struct regmap *regmap,= enum bmi160_int_pin pin, > =C2=A0 int_out_ctrl_shift =3D BMI160_INT1_OUT_CTRL_SHIFT; > =C2=A0 int_latch_mask =3D BMI160_INT1_LATCH_MASK; > =C2=A0 int_map_mask =3D BMI160_INT1_MAP_DRDY_EN; > + pin_name =3D "INT1"; > =C2=A0 break; > =C2=A0 case BMI160_PIN_INT2: > =C2=A0 int_out_ctrl_shift =3D BMI160_INT2_OUT_CTRL_SHIFT; > =C2=A0 int_latch_mask =3D BMI160_INT2_LATCH_MASK; > =C2=A0 int_map_mask =3D BMI160_INT2_MAP_DRDY_EN; > + pin_name =3D "INT2"; > =C2=A0 break; > + default: > + return -EINVAL; > =C2=A0 } > =C2=A0 int_out_ctrl_mask =3D BMI160_INT_OUT_CTRL_MASK << int_out_ctrl_shi= ft; > =C2=A0 > @@ -612,17 +616,8 @@ static int bmi160_config_pin(struct regmap *regmap, = enum bmi160_int_pin pin, > =C2=A0 ret =3D bmi160_write_conf_reg(regmap, BMI160_REG_INT_MAP, > =C2=A0 =C2=A0=C2=A0=C2=A0 int_map_mask, int_map_mask, > =C2=A0 =C2=A0=C2=A0=C2=A0 write_usleep); > - if (ret) { > - switch (pin) { > - case BMI160_PIN_INT1: > - pin_name =3D "INT1"; > - break; > - case BMI160_PIN_INT2: > - pin_name =3D "INT2"; > - break; > - } > + if (ret) > =C2=A0 dev_err(dev, "Failed to configure %s IRQ pin", pin_name); > - } > =C2=A0 > =C2=A0 return ret; > =C2=A0}