Description
In the Linux kernel, the following vulnerability has been resolved:

USB: gadget: dummy-hcd: Fix wait for outstanding request completions

The dummy-hcd driver emulates synchronize_irq() by waiting until its
private callback_usage counter drops to 0 (with the private lock not
held). This counter is incremented whenever a gadget driver callback
occurs (which requires the private lock to be dropped), but not when a
request completion handler is called.

This is an oversight. Request completion is triggered by timer
interrupts (emulating device IRQs in a real UDC), and the interrupt
handlers are supposed to have completed when the synchronize_irq()
emulation routine returns -- they aren't supposed to be in the middle
of a completion callback. If this happens it can lead to a gadget
driver's unbind routine running before all outstanding request
completions have finished, maybe even allowing the gadget driver's
module to be unloaded while a completion handler is still running.

Fix the oversight by incrementing the callback_usage value across
request completion callbacks.
Published: 2026-10-18
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Sun, 18 Oct 2026 16:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: USB: gadget: dummy-hcd: Fix wait for outstanding request completions The dummy-hcd driver emulates synchronize_irq() by waiting until its private callback_usage counter drops to 0 (with the private lock not held). This counter is incremented whenever a gadget driver callback occurs (which requires the private lock to be dropped), but not when a request completion handler is called. This is an oversight. Request completion is triggered by timer interrupts (emulating device IRQs in a real UDC), and the interrupt handlers are supposed to have completed when the synchronize_irq() emulation routine returns -- they aren't supposed to be in the middle of a completion callback. If this happens it can lead to a gadget driver's unbind routine running before all outstanding request completions have finished, maybe even allowing the gadget driver's module to be unloaded while a completion handler is still running. Fix the oversight by incrementing the callback_usage value across request completion callbacks.
Title USB: gadget: dummy-hcd: Fix wait for outstanding request completions
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-18T15:47:57.358Z

Reserved: 2026-09-25T10:25:14.368Z

Link: CVE-2026-98765

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-18T16:17:30.323

Modified: 2026-10-18T16:17:30.323

Link: CVE-2026-98765

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.