In the Linux kernel, the following vulnerability has been resolved:
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():
<pre>
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 */
</pre>
lpc32xx_adc_isr() calls complete():
<pre>
complete(&st->completion);
</pre>
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().