From: Maxwell Doose Date: Sat, 13 Jun 2026 00:58:10 +0000 (-0500) Subject: iio: adc: lpc32xx: Initialize completion before requesting IRQ X-Git-Tag: v7.2-rc3~3^2^2~20 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e561b35633f450ee607e87a6401d97f156a0cd54;p=thirdparty%2Fkernel%2Flinux.git iio: adc: lpc32xx: Initialize completion before requesting IRQ In the report from Jaeyoung Chung: "lpc32xx_adc_probe() in drivers/iio/adc/lpc32xx_adc.c registers its interrupt handler with devm_request_irq() before it initializes st->completion with init_completion(). If an interrupt arrives after devm_request_irq() and before init_completion(), the handler calls complete() on an uninitialized completion, causing a kernel panic. The probe path, in lpc32xx_adc_probe(): iodev = devm_iio_device_alloc(&pdev->dev, sizeof(*st)); /* st kzalloc-zeroed */ ... retval = devm_request_irq(&pdev->dev, irq, lpc32xx_adc_isr, 0, LPC32XXAD_NAME, st); /* register handler */ ... init_completion(&st->completion); /* initialize completion */ lpc32xx_adc_isr() calls complete(): complete(&st->completion); If the device raises an interrupt before init_completion() runs, complete() acquires the uninitialized wait.lock and walks the zeroed task_list in swake_up_locked(). The zeroed task_list makes list_empty() return false, so swake_up_locked() dereferences a NULL list entry, triggering a KASAN wild-memory-access." Fix the chance of a spurious IRQ causing an uninitialized pointer dereference by moving init_completion() above devm_request_irq(). Fixes: 7901b2a1453e ("staging:iio:adc:lpc32xx rename local state structure to _state") Reported-by: Sangyun Kim Reported-by: Kyungwook Boo Reported-by: Jaeyoung Chung Closes: https://lore.kernel.org/linux-iio/20260610115700.774689-1-jjy600901@snu.ac.kr/ Signed-off-by: Maxwell Doose Reviewed-by: Vladimir Zapolskiy Cc: Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/adc/lpc32xx_adc.c b/drivers/iio/adc/lpc32xx_adc.c index 43a7bc8158b5..db3a602327ff 100644 --- a/drivers/iio/adc/lpc32xx_adc.c +++ b/drivers/iio/adc/lpc32xx_adc.c @@ -179,6 +179,8 @@ static int lpc32xx_adc_probe(struct platform_device *pdev) if (irq < 0) return irq; + init_completion(&st->completion); + retval = devm_request_irq(&pdev->dev, irq, lpc32xx_adc_isr, 0, LPC32XXAD_NAME, st); if (retval < 0) { @@ -197,8 +199,6 @@ static int lpc32xx_adc_probe(struct platform_device *pdev) platform_set_drvdata(pdev, iodev); - init_completion(&st->completion); - iodev->name = LPC32XXAD_NAME; iodev->info = &lpc32xx_adc_iio_info; iodev->modes = INDIO_DIRECT_MODE;