CVE-2021-47437

What it actually does

The vulnerability causes a deadlock in the adis16475 IIO driver when setting the sampling frequency due to incorrect use of a locked register write function and failure to release a lock on the success path.

Why it matters to the business

Systems using affected Linux kernel versions with this sensor may experience kernel deadlocks, leading to system unresponsiveness and potential denial of service for sensor-dependent operations.

How an attack unfolds

An attacker with local access triggers the frequency setting code path in the driver, causing the deadlock due to the locking errors introduced in prior changes to sync scale mode handling.

How to fix it

Apply the upstream kernel patch that replaces the locked write call with its unlocked variant and ensures the lock is released on the success path. Update to a patched kernel version containing the fix for iio: adis16475.

How to confirm the fix worked

Inspect the driver source for the corrected adis_write_reg call and lock release logic on all paths; perform runtime testing of frequency set operations to confirm absence of deadlock under concurrent access.

Typical attack path

1. Obtain local access to the affected Linux system
2. Interact with the adis16475 IIO device to invoke frequency configuration
3. Trigger the flawed lock handling in adis_write_reg_16 and success path
4. Induce kernel deadlock halting driver and dependent processes

How to detect it

Examine kernel logs for deadlock warnings, hung task reports, or stack traces involving adis16475 frequency or register write functions; monitor for processes stuck waiting on the driver lock.

What your security team should do

• Apply kernel updates containing the deadlock fix as soon as available from distribution vendors
• Audit systems for presence of the adis16475 driver and prioritize patching where the sensor is in use
• Test patched kernels in representative hardware environments before broad deployment