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Sun, 21 Jun 2026 12:30:49 -0700 (PDT) From: Biren Pandya To: Jonathan Cameron , David Lechner , =?UTF-8?q?Nuno=20S=C3=A1?= , Andy Shevchenko , Biren Pandya , Sakari Ailus , Linus Walleij , linux-iio@vger.kernel.org (open list:IIO SUBSYSTEM AND DRIVERS), linux-kernel@vger.kernel.org (open list) Subject: [PATCH v2] iio: accel: kxsd9: fix runtime PM leaks and unchecked returns Date: Mon, 22 Jun 2026 01:00:31 +0530 Message-ID: <20260621193036.78549-2-birenpandya@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260615200330.1234-1-birenpandya@gmail.com> References: <20260615200330.1234-1-birenpandya@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The kxsd9 driver uses pm_runtime_get_sync() without checking its return value, which can lead to silent failures. It also relies on manual pm_runtime_put_autosuspend() calls, which is prone to leaks. Specifically, kxsd9_write_raw() contains a bug where returning -EINVAL bypasses the pm_runtime_put_autosuspend() call, leaving the device powered on. Modernize the runtime PM handling to fix these issues: - kxsd9_write_raw() & kxsd9_read_raw(): Use the scoped PM_RUNTIME_ACQUIRE_IF_ENABLED_AUTOSUSPEND() macro to safely automate cleanup on function return and remove all manual puts/error gotos. - kxsd9_buffer_preenable(): Use pm_runtime_resume_and_get() to safely check for errors and handle usage-counter unwinding. - kxsd9_common_remove(): Use pm_runtime_resume_and_get(), and reverse the disable ordering to call pm_runtime_disable() before powering down to prevent background RPM race conditions. Fixes: 9a9a369d6178 ("iio: accel: kxsd9: Deploy system and runtime PM") Signed-off-by: Biren Pandya --- Changes in v2: - Changed subject to reflect broader PM modernization. - In kxsd9_common_remove(), reversed the order to call pm_runtime_disable() before kxsd9_power_down() to prevent background RPM race conditions. - Used standard error checking idiom in kxsd9_common_remove() (Andy). - Clarified commit message regarding the exact write_raw() bug and added the Fixes tag (Jonathan). drivers/iio/accel/kxsd9.c | 47 ++++++++++++++++++--------------------- 1 file changed, 22 insertions(+), 25 deletions(-) diff --git a/drivers/iio/accel/kxsd9.c b/drivers/iio/accel/kxsd9.c index 4717d80fc24a..7aa23ae64b7c 100644 --- a/drivers/iio/accel/kxsd9.c +++ b/drivers/iio/accel/kxsd9.c @@ -139,68 +139,63 @@ static int kxsd9_write_raw(struct iio_dev *indio_dev, int val2, long mask) { - int ret = -EINVAL; struct kxsd9_state *st = iio_priv(indio_dev); - pm_runtime_get_sync(st->dev); + PM_RUNTIME_ACQUIRE_IF_ENABLED_AUTOSUSPEND(st->dev, pm); + if (PM_RUNTIME_ACQUIRE_ERR(&pm)) + return PM_RUNTIME_ACQUIRE_ERR(&pm); if (mask == IIO_CHAN_INFO_SCALE) { /* Check no integer component */ if (val) return -EINVAL; - ret = kxsd9_write_scale(indio_dev, val2); + return kxsd9_write_scale(indio_dev, val2); } - pm_runtime_put_autosuspend(st->dev); - - return ret; + return -EINVAL; } static int kxsd9_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { - int ret = -EINVAL; struct kxsd9_state *st = iio_priv(indio_dev); unsigned int regval; __be16 raw_val; u16 nval; + int ret; - pm_runtime_get_sync(st->dev); + PM_RUNTIME_ACQUIRE_IF_ENABLED_AUTOSUSPEND(st->dev, pm); + if (PM_RUNTIME_ACQUIRE_ERR(&pm)) + return PM_RUNTIME_ACQUIRE_ERR(&pm); switch (mask) { case IIO_CHAN_INFO_RAW: ret = regmap_bulk_read(st->map, chan->address, &raw_val, sizeof(raw_val)); if (ret) - goto error_ret; + return ret; nval = be16_to_cpu(raw_val); /* Only 12 bits are valid */ nval >>= 4; *val = nval; - ret = IIO_VAL_INT; - break; + return IIO_VAL_INT; case IIO_CHAN_INFO_OFFSET: /* This has a bias of -2048 */ *val = KXSD9_ZERO_G_OFFSET; - ret = IIO_VAL_INT; - break; + return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: ret = regmap_read(st->map, KXSD9_REG_CTRL_C, ®val); if (ret < 0) - goto error_ret; + return ret; *val = 0; *val2 = kxsd9_micro_scales[regval & KXSD9_CTRL_C_FS_MASK]; - ret = IIO_VAL_INT_PLUS_MICRO; - break; + return IIO_VAL_INT_PLUS_MICRO; } -error_ret: - pm_runtime_put_autosuspend(st->dev); - - return ret; + return -EINVAL; }; static irqreturn_t kxsd9_trigger_handler(int irq, void *p) @@ -239,9 +234,7 @@ static int kxsd9_buffer_preenable(struct iio_dev *indio_dev) { struct kxsd9_state *st = iio_priv(indio_dev); - pm_runtime_get_sync(st->dev); - - return 0; + return pm_runtime_resume_and_get(st->dev); } static int kxsd9_buffer_postdisable(struct iio_dev *indio_dev) @@ -476,13 +469,17 @@ void kxsd9_common_remove(struct device *dev) { struct iio_dev *indio_dev = dev_get_drvdata(dev); struct kxsd9_state *st = iio_priv(indio_dev); + int ret; iio_triggered_buffer_cleanup(indio_dev); iio_device_unregister(indio_dev); - pm_runtime_get_sync(dev); - pm_runtime_put_noidle(dev); + ret = pm_runtime_resume_and_get(dev); pm_runtime_disable(dev); + if (ret < 0) + return; + kxsd9_power_down(st); + pm_runtime_put_noidle(dev); } EXPORT_SYMBOL_NS(kxsd9_common_remove, "IIO_KXSD9"); -- 2.50.1 (Apple Git-155)