ad_sd_buffer_postenable() allocates sigma_delta->samples_buf with devm_krealloc() at runtime, so its devres entry sits after all probe-time entries of the driver. devm resources are released in reverse allocation order, which means unbind frees samples_buf before iio_device_unregister() disables the buffers and detaches the trigger pollfunc. The data ready IRQ is still enabled at that point, so ad_sd_trigger_handler() can still run and memcpy() incoming samples into the freed samples_buf. Fix this by preallocating the buffer in devm_ad_sd_setup_buffer_and_trigger(), before the triggered buffer and the IRQ are set up, so it is freed only after iio_device_unregister() has drained the trigger handler via free_irq(). Size it for the worst case of all sequencer slots being active; ad_sd_validate_scan_mask() already caps the number of active channels at num_slots. This issue was found by an in-house static analysis tool. Fixes: 8bea9af887de ("iio: adc: ad_sigma_delta: Add sequencer support") Cc: stable@vger.kernel.org Co-developed-by: Song Li Signed-off-by: Song Li Signed-off-by: Fan Wu --- drivers/iio/adc/ad_sigma_delta.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c index 1b41029..4f982c6 100644 --- a/drivers/iio/adc/ad_sigma_delta.c +++ b/drivers/iio/adc/ad_sigma_delta.c @@ -498,7 +498,6 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type; struct spi_transfer *xfer = sigma_delta->sample_xfer; unsigned int i, slot, channel; - u8 *samples_buf; int ret; if (sigma_delta->num_slots == 1) { @@ -530,7 +529,7 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) xfer[1].bits_per_word = scan_type->realbits; xfer[1].len = spi_bpw_to_bytes(scan_type->realbits); } else { - unsigned int samples_buf_size, scan_size; + unsigned int scan_size; if (sigma_delta->active_slots > 1) { ret = ad_sigma_delta_append_status(sigma_delta, true); @@ -538,17 +537,6 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) return ret; } - samples_buf_size = - ALIGN(slot * BITS_TO_BYTES(scan_type->storagebits), - sizeof(s64)); - samples_buf_size += sizeof(s64); - samples_buf = devm_krealloc(&sigma_delta->spi->dev, - sigma_delta->samples_buf, - samples_buf_size, GFP_KERNEL); - if (!samples_buf) - return -ENOMEM; - - sigma_delta->samples_buf = samples_buf; scan_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift); /* For 24-bit data, there is an extra byte of padding. */ xfer[1].rx_buf = &sigma_delta->rx_buf[scan_size == 3 ? 1 : 0]; @@ -855,6 +843,24 @@ int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indi indio_dev->setup_ops = &ad_sd_buffer_setup_ops; } else { + const struct iio_scan_type *scan_type = + &indio_dev->channels[0].scan_type; + unsigned int samples_buf_size; + + /* + * Worst-case size: all sequencer slots can be active, capped + * at num_slots by ad_sd_validate_scan_mask(). + */ + samples_buf_size = + ALIGN(sigma_delta->num_slots * + BITS_TO_BYTES(scan_type->storagebits), + sizeof(s64)); + samples_buf_size += sizeof(s64); + sigma_delta->samples_buf = + devm_kzalloc(dev, samples_buf_size, GFP_KERNEL); + if (!sigma_delta->samples_buf) + return -ENOMEM; + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, &iio_pollfunc_store_time, &ad_sd_trigger_handler,