CVE-2023-54136

What it actually does

Failure to release allocated DMA buffers on error return paths in the sprd serial driver's _probe() function, causing a memory leak of DMA resources.

Why it matters to the business

Repeated driver probe failures on affected Linux systems can gradually exhaust available memory, leading to degraded performance, instability, or denial of service in long-running embedded or server environments using this hardware.

How an attack unfolds

An attacker triggers repeated initialization failures of the sprd serial driver through hardware faults, module reload cycles, or error injection; each failure leaks DMA memory without release, accumulating until system resources are depleted.

How to fix it

Update the Linux kernel to the fixed commit c65be6ad55e5e45f8c4e40e1d8d7fe0e21b26e77 or later stable releases containing the DMA buffer release on probe failure; rebuild and deploy the updated kernel image.

How to confirm the fix worked

Confirm the presence of the DMA buffer release logic on probe error paths in the sprd serial driver source; test probe failure scenarios and verify no DMA memory leaks via kmemleak or slabinfo before and after the update.

Typical attack path

1. Locate systems exposing the sprd serial driver in the Linux kernel
2. Cause repeated probe() failures via hardware manipulation or driver reload
3. Monitor kernel memory consumption for gradual increase without corresponding workload
4. Sustain the failure condition until memory pressure leads to system impact

How to detect it

Review kernel logs for repeated sprd probe failures; use kmemleak reports or slabtop to identify unreleased DMA allocations from the sprd driver; correlate with module load/unload events over extended periods.

What your security team should do

• Prioritize kernel updates on systems using sprd serial hardware given the published fix
• Monitor EPSS and exploit maturity trends for any increase in activity
• Audit embedded Linux deployments for sprd driver usage and schedule patching
• Enable kernel memory leak detectors in test environments to validate remediation