CVE-2024-42085

What it actually does

The flaw is a redundant spin_lock_irqsave acquisition on dwc->lock inside the OTG-mode gadget suspend/resume path, causing an immediate deadlock when CONFIG_USB_DWC3_DUAL_ROLE is enabled and the system enters suspend.

Why it matters to the business

Systems using the affected Linux kernel with dual-role USB controllers may hang during power-state transitions, interrupting workloads, preventing clean shutdowns, and requiring manual intervention or reboots that can lead to data loss or extended downtime.

How an attack unfolds

An attacker with the ability to issue a suspend command (echo mem > /sys/power/state) on a dual-role DWC3 device triggers the nested lock acquisition; no remote code execution or privilege escalation is involved, only a local denial-of-service via deadlock.

How to fix it

Upgrade to a fixed kernel version: 5.15.162 or later stable releases containing commit 8731a0b180f6b5d52397c7aeea6eda9511a467a7. Rebuild and reboot with the patched kernel; no configuration changes are required.

How to confirm the fix worked

Confirm the running kernel contains the fix commit or is at least version 5.15.162; attempt a suspend/resume cycle on a dual-role DWC3 device and verify the operation completes without deadlock or kernel warnings.

Typical attack path

1. Obtain local access or command execution on a Linux system configured with CONFIG_USB_DWC3_DUAL_ROLE
2. Ensure a DWC3 controller is present and operating in OTG/dual-role mode
3. Issue a system suspend request (e.g., via /sys/power/state)
4. Trigger the deadlock in dwc3_suspend_common -> dwc3_gadget_suspend -> dwc3_gadget_soft_disconnect

How to detect it

Inspect kernel logs (dmesg, /var/log/kern.log, journalctl) for repeated spinlock deadlock warnings or stack traces referencing dwc3_suspend_common and dwc3_gadget_suspend around the time of suspend attempts; no post-exploitation artifacts are expected because the condition is a hang rather than code execution.

What your security team should do

• Prioritize patching production kernels that use DWC3 dual-role USB within the next maintenance window
• Add kernel version checks to vulnerability scanning and asset inventory tools
• Monitor vendor and distribution advisories for backported fixes in LTS branches