6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marco Chen [ Upstream commit f0ea4824deebf21dacfbe397c4b0a5fd3e745a8d ] The interrupt is requested in max30102_probe() and stays enabled for the lifetime of the device, but indio_dev->active_scan_mask is only valid while a buffer is enabled. When an interrupt arrives while no buffer is enabled, the handler dereferences the NULL active_scan_mask: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Call trace: __bitmap_weight+0x64/0x98 (P) max30102_interrupt_handler+0x48/0x160 [max30102] Call max30102_fifo_count() at the top of the handler and return early unless it reports a FIFO sample is ready. Because FIFO_RDY is the only interrupt source enabled in max30102_chip_init(), an invocation of max30102_interrupt_handler() without the FIFO_RDY interrupt status bit set carries no data to read and can return before touching active_scan_mask. A negative return from max30102_fifo_count() indicates a failed interrupt status read and is treated the same way. Fixes: 90579b69e94b ("iio: health: max30102: Add MAX30105 support") Suggested-by: Jonathan Cameron Signed-off-by: Marco Chen Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/iio/health/max30102.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/iio/health/max30102.c b/drivers/iio/health/max30102.c index 43c16fcdeae19..9419cc62a2a4d 100644 --- a/drivers/iio/health/max30102.c +++ b/drivers/iio/health/max30102.c @@ -292,9 +292,15 @@ static irqreturn_t max30102_interrupt_handler(int irq, void *private) { struct iio_dev *indio_dev = private; struct max30102_data *data = iio_priv(indio_dev); - unsigned int measurements = bitmap_weight(indio_dev->active_scan_mask, - iio_get_masklength(indio_dev)); - int ret, cnt = 0; + unsigned int measurements; + int ret, cnt; + + cnt = max30102_fifo_count(data); + if (cnt <= 0) + return IRQ_HANDLED; + + measurements = bitmap_weight(indio_dev->active_scan_mask, + iio_get_masklength(indio_dev)); mutex_lock(&data->lock); -- 2.53.0