patch "iio: adc: spear: Initialize completion before requesting IRQ" added to char-misc-linus

This is a note to let you know that I've just added the patch titled

iio: adc: spear: Initialize completion before requesting IRQ

to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 3ee2128b6f0eb0be7b6cb8f6e0f1f113a65201a0 Mon Sep 17 00:00:00 2001
From: Maxwell Doose <[email protected]>
Date: Fri, 12 Jun 2026 19:58:11 -0500
Subject: iio: adc: spear: Initialize completion before requesting IRQ

In the report from Jaeyoung Chung:

"spear_adc_probe() in drivers/iio/adc/spear_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 spear_adc_probe():

    iodev = devm_iio_device_alloc(&pdev->dev, sizeof(*st)); /* st kzalloc-zeroed */
    ...
    retval = devm_request_irq(&pdev->dev, irq, spear_adc_isr, 0,
                              LPC32XXAD_NAME, st);           /* register handler */
    ...
    init_completion(&st->completion);                       /* initialize completion */

spear_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().

---
 drivers/iio/adc/spear_adc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

index 4be722406bb5..ab02a14682ed 100644
@@ -283,6 +283,7 @@ static int spear_adc_probe(struct platform_device *pdev)
 	st = iio_priv(indio_dev);
 	st->dev = dev;
 
+	init_completion(&st->completion);
 	mutex_init(&st->lock);
 
 	/*

@@ -329,8 +330,6 @@ static int spear_adc_probe(struct platform_device *pdev)
 
 	spear_adc_configure(st);
 
-	init_completion(&st->completion);
-
 	indio_dev->name = SPEAR_ADC_MOD_NAME;
 	indio_dev->info = &spear_adc_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;

2.55.0