usb: gadget: u_serial: Fix race condition in TTY wakeup
A race condition occurs when gs_start_io() calls either gs_start_rx() or
gs_start_tx(), as those functions briefly drop the port_lock for
usb_ep_queue(). This allows gs_close() and gserial_disconnect() to clear
port.tty and port_usb, respectively.
Use the null-safe TTY Port helper function to wake up TTY.
Example
CPU1: CPU2:
gserial_connect() // lock
gs_close() // await lock
gs_start_rx() // unlock
usb_ep_queue()
gs_close() // lock, reset port.tty and unlock
gs_start_rx() // lock
tty_wakeup() // NPE
Metrics
Affected Vendors & Products
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4327-1 | linux security update |
Debian DLA |
DLA-4328-1 | linux-6.1 security update |
Debian DSA |
DSA-5973-1 | linux security update |
Debian DSA |
DSA-5975-1 | linux security update |
EUVD |
EUVD-2025-22693 | In the Linux kernel, the following vulnerability has been resolved: usb: gadget: u_serial: Fix race condition in TTY wakeup A race condition occurs when gs_start_io() calls either gs_start_rx() or gs_start_tx(), as those functions briefly drop the port_lock for usb_ep_queue(). This allows gs_close() and gserial_disconnect() to clear port.tty and port_usb, respectively. Use the null-safe TTY Port helper function to wake up TTY. Example CPU1: CPU2: gserial_connect() // lock gs_close() // await lock gs_start_rx() // unlock usb_ep_queue() gs_close() // lock, reset port.tty and unlock gs_start_rx() // lock tty_wakeup() // NPE |
Ubuntu USN |
USN-7774-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7774-2 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-7774-3 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7775-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-7775-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7776-1 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-7775-3 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7774-4 | Linux kernel (KVM) vulnerabilities |
Ubuntu USN |
USN-7774-5 | Linux kernel (NVIDIA Tegra IGX) vulnerabilities |
Ubuntu USN |
USN-7879-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7879-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7880-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-7879-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7879-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7934-1 | Linux kernel (Azure) vulnerabilities |
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Mon, 22 Dec 2025 22:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Debian
Debian debian Linux |
|
| Weaknesses | CWE-362 | |
| CPEs | cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc4:*:*:*:*:*:* |
|
| Vendors & Products |
Debian
Debian debian Linux |
|
| Metrics |
cvssV3_1
|
cvssV3_1
|
Mon, 03 Nov 2025 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Tue, 29 Jul 2025 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-476 | |
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Sat, 26 Jul 2025 11:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Fri, 25 Jul 2025 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: usb: gadget: u_serial: Fix race condition in TTY wakeup A race condition occurs when gs_start_io() calls either gs_start_rx() or gs_start_tx(), as those functions briefly drop the port_lock for usb_ep_queue(). This allows gs_close() and gserial_disconnect() to clear port.tty and port_usb, respectively. Use the null-safe TTY Port helper function to wake up TTY. Example CPU1: CPU2: gserial_connect() // lock gs_close() // await lock gs_start_rx() // unlock usb_ep_queue() gs_close() // lock, reset port.tty and unlock gs_start_rx() // lock tty_wakeup() // NPE | |
| Title | usb: gadget: u_serial: Fix race condition in TTY wakeup | |
| References |
|
|
Projects
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-11-03T17:38:09.442Z
Reserved: 2025-04-16T04:51:24.018Z
Link: CVE-2025-38448
No data.
Status : Analyzed
Published: 2025-07-25T16:15:30.317
Modified: 2025-12-22T21:53:51.967
Link: CVE-2025-38448
OpenCVE Enrichment
Updated: 2025-07-26T11:22:03Z
Debian DLA
Debian DSA
EUVD
Ubuntu USN