CVE-2024-43822

What it actually does

Failed devm_kzalloc in pcmdevice_i2c_probe assigns -ENOMEM to ret then passes a null pointer to pcmdevice_remove, resulting in a null pointer dereference.

Why it matters to the business

Unexpected system crashes or instability on affected audio devices, with potential downtime across 178 downstream dependents; no ransomware usage or CISA deadline applies.

How an attack unfolds

An attacker triggers the I2C probe path under memory pressure so the allocation fails; the flawed error path then dereferences the null device pointer during cleanup, causing a kernel fault.

How to fix it

Apply the upstream fix that returns the error code immediately after a failed devm_kzalloc instead of continuing to the remove call; update to a kernel containing the resolution for the PCM6240 driver.

How to confirm the fix worked

Inspect the pcmdevice_i2c_probe function to confirm the early return after kzalloc failure; verify the driver no longer reaches pcmdevice_remove with a null pointer on allocation error.

Typical attack path

1. Trigger device probe under low-memory conditions
2. Force devm_kzalloc failure in pcmdevice_i2c_probe
3. Allow the erroneous ret assignment and subsequent pcmdevice_remove call with null pointer
4. Induce kernel panic or denial of service via dereference

How to detect it

Review kernel logs for oops traces referencing pcmdevice_i2c_probe or pcmdevice_remove with null pointers; look for allocation failure messages immediately preceding driver removal calls.

What your security team should do

• Prioritize patching affected Linux kernels containing the PCM6240 driver
• Monitor for kernel oops or null dereference reports in audio device initialization logs
• Test error paths under memory pressure on systems using the driver