CVE-2021-47314

What it actually does

The driver fails to release memory allocated for its private structure when the probe routine encounters an error, leaving the allocation orphaned.

Why it matters to the business

Repeated probe failures on systems using the affected hardware can gradually exhaust kernel memory, leading to degraded performance or eventual instability.

How an attack unfolds

An attacker would need to cause repeated probe failures of the fsl_ifc driver, for example by manipulating hardware or module loading conditions, to trigger the leak; the low EPSS score and lack of KEV listing indicate this path is not observed in the wild.

How to fix it

Apply a kernel update that incorporates the resource-managed allocation fix for the fsl_ifc driver; rebuild and redeploy any custom kernels or distributions that include the vulnerable code.

How to confirm the fix worked

Confirm the presence of the resource-managed allocation change (devm_kzalloc or equivalent) in the fsl_ifc probe error path of the running kernel source or binary.

Typical attack path

1. Trigger conditions that cause the fsl_ifc probe to fail
2. Observe gradual increase in kernel memory usage without corresponding allocations
3. Repeat failure events to amplify the leak until system impact occurs

How to detect it

Review kernel logs for repeated fsl_ifc probe failure messages and correlate with memory usage counters; inspect dmesg or journalctl output around module load times for allocation patterns without corresponding frees.

What your security team should do

• Prioritize kernel updates on systems that load the fsl_ifc driver
• Monitor kernel memory statistics for unexpected growth correlated with driver probe events
• Review device-tree or hardware configurations that could induce probe failures