CVE-2024-35822

What it actually does

A WARN_ON_ONCE in usb_ep_queue can be triggered when the mass storage gadget function attempts to queue a request after another thread has already disabled the endpoint, with no actual driver failure occurring.

Why it matters to the business

Produces spurious kernel warnings that may cause unnecessary log noise, alert fatigue, or operational confusion during USB gadget operations on affected systems; low overall risk given the non-security nature of the change.

How an attack unfolds

The condition can be reached during normal concurrent operation of the mass storage function's main thread and endpoint disable paths; because the change merely downgrades a warning to debug output and introduces no code execution or privilege issues, no attacker-controlled exploitation path exists.

How to fix it

Update the Linux kernel to a version containing the fix that replaces WARN_ON_ONCE with pr_debug in usb_ep_queue; apply the corresponding package update for your distribution.

How to confirm the fix worked

Confirm the kernel source no longer contains WARN_ON_ONCE at drivers/usb/gadget/udc/core.c:294 in usb_ep_queue and verify absence of the warning during mass storage gadget use after the update.

Typical attack path

1. Trigger mass storage gadget activity that queues USB requests
2. Concurrently disable the endpoint from another thread
3. Observe the resulting kernel warning (no further impact)

How to detect it

Search kernel logs for the specific usb_ep_queue warning stack trace involving fsg_main_thread; no post-exploitation artifacts are expected because the issue produces only a warning.

What your security team should do

• Apply the kernel update at the next maintenance window
• Review USB gadget configurations for mass storage use cases
• Monitor kernel logs for similar warnings in other subsystems